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{{Infobox number
| number = 12
| numeral = [[Duodecimal|duodecimal]]
| divisor = 1, 2, 3, 4, 6, 12
| greek prefix = dodeca-
| latin prefix = duodeca-
|lang1=[[Malayalam numerals|Malayalam]]
|lang1 symbol=൰൨
|lang2=[[Bengali numerals|Bengali]]
|lang2 symbol=১২

}}

'''12''' ('''twelve''') is the [[Natural number|natural number]] following [[11 (number)|11]] and preceding [[13 (number)|13]]. Twelve is a [[Superior highly composite number|superior highly composite number]], divisible by the numbers 2, 3, 4, and 6.

It is the number of years required for an [[Astronomy:Jupiter#Pre-telescopic research|orbital period of Jupiter]]. It is central to many systems of timekeeping, including the [[Gregorian calendar|Western calendar]] and [[Time|units of time of day]] and frequently appears in the world's major religions.

{{anchor|Etymology}}

==Name==
Twelve is the largest number with a single-syllable name in [[Social:English language|English]]. Early Germanic numbers have been theorized to have been non-[[Decimal|decimal]]: evidence includes the unusual phrasing of [[11 (number)|eleven]] and twelve, the [[Long hundred|former use of "hundred"]] to refer to groups of [[120 (number)|120]], and the presence of glosses such as "tentywise" or "ten-count" in medieval texts showing that writers could not presume their readers would normally understand them that way.<ref>{{cite book |last=Gordon |first=E. V. |title=Introduction to Old Norse |year=1957 |publisher=Clarendon Press |location=Oxford, England |pages=292–293 |url=https://www.scribd.com/doc/49127454/Introduction-to-Old-Norse-by-E-V-Gordon |access-date=2017-09-08 |archive-date=2016-04-15 |archive-url=https://web.archive.org/web/20160415205641/https://www.scribd.com/doc/49127454/Introduction-to-Old-Norse-by-E-V-Gordon |url-status=dead }}</ref><ref>{{cite journal |last=Stevenson |first=W. H. |title = The Long Hundred and its Use in England|journal=Archaeological Review|date=December 1899 |volume = 4 |issue = 5 |pages=313–317 }}</ref><ref name=Goodare>{{cite journal |last=Goodare|first=Julian |title=The Long Hundred in medieval and early modern Scotland |journal=Proceedings of the Society of Antiquaries of Scotland|year=1993|volume=123 |pages=395–418 |doi=10.9750/PSAS.123.395.418 |s2cid=162146336 |url = http://ads.ahds.ac.uk/catalogue/adsdata/arch-352-1/dissemination/pdf/vol_123/123_395_418.pdf }}</ref> Such uses gradually disappeared with the introduction of [[Arabic numerals]] during the 12th-century Renaissance.

Derived from [[Social:Old English|Old English]], ''{{lang|ang|twelf}}'' and ''{{lang|ang|tuelf}}'' are first attested in the 10th-century Lindisfarne Gospels' Book of John.{{NoteTag|Specially, a passage referring to Judas Iscariot as "one of the twelve" (''{{lang|ang|an of ðæm tuelfum}}'').<ref>{{bibleref|John|6:71|KJV}}.</ref>}}<ref name="oed"/> It has cognates in every Germanic language (e.g. German {{Lang|de|zwölf}}), whose [[Social:Proto-Germanic language|Proto-Germanic]] ancestor has been reconstructed as ''{{lang|gem-x-proto|twaliƀi...}}'', from ''{{lang|gem-x-proto|twa}}'' ("two") and suffix ''{{lang|gem-x-proto|-lif-}}'' or ''{{lang|gem-x-proto|-liƀ-}}'' of uncertain meaning.<ref name="oed" /> It is sometimes compared with the [[Social:Lithuanian language|Lithuanian]] ''{{lang|lt|dvýlika}}'', although ''{{lang|lt|-lika}}'' is used as the suffix for all numbers from 11 to 19 (analogous to "-teen").<ref name="oed" /> Every other Indo-European language instead uses a form of "two"+"ten", such as the [[Social:Latin|Latin]] ''{{lang|la|duōdecim}}''.<ref name="oed" /> The usual [[Ordinal number|ordinal form]] is "twelfth" but "dozenth" or "duodecimal" (from the Latin word) is also used in some contexts, particularly base-12 numeration. Similarly, a group of twelve things is usually a "[[Dozen|dozen]]" but may also be referred to as a "dodecad" or "duodecad". The adjective referring to a group of twelve is "duodecuple".

As with eleven,<ref name="oedgoesto">''Oxford English Dictionary'', 1st ed. "eleven, ''adj.'' and ''n.''" Oxford University Press (Oxford), 1891.</ref> the earliest forms of twelve are often considered to be connected with Proto-Germanic ''{{lang|gem-x-proto|liƀan}}'' or ''{{lang|gem-x-proto|liƀan}}'' ("to leave"), with the implicit meaning that "two is left" after having already counted to ten.<ref name="oed">''Oxford English Dictionary'', 1st ed. "twelve, ''adj.'' and ''n.''" Oxford University Press (Oxford), 1916.</ref> The Lithuanian suffix is also considered to share a similar development.<ref name="oed" /> The suffix ''{{lang|gem-x-proto|-lif-}}'' has also been connected with reconstructions of the Proto-Germanic for ten.<ref name="oedgoesto"/><ref>{{citation |last=Dantzig |first=Tobias |year = 1930 |title = Number: The Language of Science }}.</ref>

As mentioned above, 12 has its own name in Germanic languages such as English ([[Dozen|dozen]]), Dutch ({{Lang|nl|dozijn}}), German ({{Lang|de|Dutzend}}), and Swedish ({{Lang|sv|dussin}}), all derived from Old French ''{{Lang|fro|dozaine}}''. It is a compound number in many other languages, e.g. Italian ''{{Lang|it|dodici}}'' (but in Spanish and Portuguese, 16, and in French, 17 is the first compound number),{{dubious|date=May 2018}} Japanese 十二 ''jūni''.{{clarify|date=May 2018}}

===Written representation===
In prose writing, ''twelve'', being the last single-syllable numeral, is sometimes taken as the last number to be written as a word, and [[13 (number)|13]] the first to be written using digits.
This is not a binding rule, and in English language tradition, it is sometimes recommended to spell out numbers up to and including either ''nine'', ''ten'' or ''twelve'', or even ''ninety-nine'' or ''one hundred''. Another system spells out all numbers written in one or two words (''sixteen'', ''twenty-seven'', ''fifteen thousand'', but ''372'' or ''15,001'').<ref>{{Cite web|url=https://owl.purdue.edu/owl/general_writing/grammar/writing_numbers.html|title=Numbers: Writing Numbers // Purdue Writing Lab|website=Purdue Writing Lab|access-date=25 February 2020}}</ref>
In German orthography, there used to be the widely followed (but unofficial) rule of spelling out numbers up to twelve (''zwölf''). The Duden{{year needed|date=May 2018}} (the German standard dictionary) mentions this rule as outdated.

==Mathematical properties==
'''12''' is the sixth [[Composite number|composite number]] and the [[Superfactorial|superfactorial]] of 3.<ref>{{Cite OEIS |A002808 |The composite numbers: numbers n of the form x*y for x > 1 and y > 1. |access-date=2023-06-15 }}</ref><ref>{{Cite web|url=https://oeis.org/A000178|title=Sloane's A000178: Superfactorials|website=The On-Line Encyclopedia of Integer Sequences|publisher=OEIS Foundation|access-date=2022-07-29}}</ref> It is the fourth [[Pronic number|pronic number]] (equal to [[3|3]] × [[4|4]]),<ref>{{Cite OEIS |A002378 |Oblong (or promic, pronic, or heteromecic) numbers |access-date=2023-06-15 }}</ref> whose digits in decimal are also successive. It is the smallest [[Abundant number|abundant number]], since it is the smallest integer for which the sum of its proper divisors ([[1|1]] + [[2|2]] + 3 + 4 + [[6|6]] = [[16 (number)|16]]) is greater than itself,<ref>{{Cite OEIS |A005101 |Abundant numbers (sum of divisors of m exceeds 2m). |access-date=2023-01-10 }}</ref> and the second [[Semiperfect number|semiperfect number]], since there is a subset of the proper divisors of 12 that add up to itself.<ref>{{Cite OEIS |A005835 |Pseudoperfect (or semiperfect) numbers n: some subset of the proper divisors of n sums to n. |access-date=2016-06-01 }}</ref> It is equal to the sum between the second pair of [[Twin prime|twin prime]]s ([[5|5]] + [[7|7]]),<ref>{{Cite OEIS |A001097 |Twin primes. |access-date=2023-06-15 }}</ref> while it is also the smallest number with exactly six [[Divisor|divisor]]s (1, 2, 3, 4, 6 and 12) which makes it the fifth [[Highly composite number|highly composite number]],<ref>{{Cite OEIS |A002182 |Highly composite numbers, definition (1): numbers n where d(n), the number of divisors of n (A000005), increases to a record. |access-date=2023-06-19 }}</ref> and since [[6|6]] is also one of them, twelve is also the fifth [[Refactorable number|refactorable number]].<ref>{{Cite OEIS |A033950 |Refactorable numbers: number of divisors of k divides k. Also known as tau numbers. |access-date=2023-06-15 }}</ref> 12, as a number with a [[Perfect number|perfect]] number of divisors (six), has a [[Divisor function|sum of divisors]] that yields the second perfect number, '''σ'''(12) = [[28 (number)|28]],<ref>{{Cite OEIS |A000396 |Perfect numbers k: k is equal to the sum of the proper divisors of k. |access-date=2023-01-10 }}</ref> and as such it is the smallest of two known [[Sublime number|sublime number]]s, which are numbers that have a [[Perfect number|perfect number]] of divisors whose sum is also perfect.<ref>{{cite web |url = https://oeis.org/A081357|title=Sloane's A081357 : Sublime numbers |website=The On-Line Encyclopedia of Integer Sequences |publisher=OEIS Foundation |access-date=2016-06-01}}</ref> 12 is the fifth [[Pell number]] (preceded by 0, 1, 2, and [[5|5]])<ref>{{Cite OEIS |A000129 |Pell numbers |access-date=2023-01-10 }}</ref> as well as the third pentagonal number,<ref>{{Cite OEIS |A000326 |Pentagonal numbers |access-date=2023-01-10 }}</ref> and a [[Harshad number]] in all bases except [[Octal|octal]].

Twelve is the number of divisors of [[60 (number)|60]] and [[90 (number)|90]], the second and third [[Unitary perfect number|unitary perfect number]]s ([[6|6]] is the first). It is also the number of distinct [[Prime number#Unique factorization|prime factor]]s that belong to the fifth unitary perfect number, the largest known, 
:<math>2^{18} \times 3 \times 5^{4} \times 7 \times 11 \times 13 \times 19 \times 37 \times 79 \times 109 \times 157 \times 313 = 146\;361\;946\;186\;458\;562\;560\;000</math><ref name=Wall1988>{{Cite journal |last=Wall |first=Charles R. |url=https://www.fq.math.ca/Scanned/26-4/wall.pdf |title=New unitary perfect numbers have at least nine odd components |journal=[[Fibonacci Quarterly]] |volume=26 |number=4 |pages=312 |year=1988 |issn=0015-0517 |mr=967649 |zbl=0657.10003 }}</ref><ref>{{Cite OEIS |A002827 |Unitary perfect numbers |access-date=2023-01-10 }}</ref>

The second perfect number, [[28 (number)|28]], is the [[Arithmetic mean|arithmetic mean]] of the twelve divisors of the fourth [[Harmonic divisor number|harmonic divisor number]], [[140 (number)|140]] (like 6, and 28), which generates an integer [[Harmonic mean|harmonic mean]] of [[5|5]].<ref>{{Cite OEIS |A000203 |Sigma n, the sum of the divisors of n |access-date=2023-01-10 }}</ref><ref>{{Cite OEIS |A001599 |Harmonic or Ore numbers: numbers n such that the harmonic mean of the divisors of n is an integer. |access-date=2023-01-10 }}</ref><ref>{{Cite OEIS |A001600 |Harmonic means of divisors of harmonic numbers. |access-date=2023-01-11 }}</ref>

If an odd [[Perfect number|perfect number]] is not divisible by [[3|3]], it will have at least twelve distinct prime factors.<ref>{{Cite journal |first=Nielsen |last=Pace P. |title=Odd perfect numbers have at least nine distinct prime factors |url=https://www.ams.org/journals/mcom/2007-76-260/S0025-5718-07-01990-4/ |journal=[[Mathematics of Computation]] |volume=76 |pages=2109–2126 |publisher=American Mathematical Society |location=Providence, R.I. |year=2007 |doi=10.1090/S0025-5718-07-01990-4 |doi-access=free |bibcode=2007MaCom..76.2109N |mr=2336286 |s2cid=2767519 |zbl=1142.11086 |arxiv=math/0602485 }}</ref>

There are 12 [[Latin square]]s of size 3 × 3, where symbols appear exactly once in each row and exactly once in each column.<ref>{{Cite OEIS |A002860 |Number of Latin squares of order n |access-date=2023-01-19 }}</ref>

There are twelve Jacobian elliptic functions and twelve cubic [[Distance-transitive graph|distance-transitive graph]]s.

A twelve-sided [[Polygon|polygon]] is a [[Dodecagon|dodecagon]]. In its regular form, it is the largest polygon that can [[Euclidean tilings by convex regular polygons#Archimedean, uniform or semiregular tilings|uniformly]] tile the plane alongside other regular polygons, as with the [[Truncated hexagonal tiling|truncated hexagonal tiling]] or the [[Truncated trihexagonal tiling|truncated trihexagonal tiling]]. There are 12 [[Euclidean tilings by convex regular polygons|regular and semiregular]] tilings when [[Chirality (mathematics)|enantiomorphic]] forms of the snub hexagonal tiling are counted separately.<ref>{{Cite book |author1=Grünbaum, Branko |author2=Shephard, G. C. |url-access=registration |url=https://archive.org/details/isbn_0716711931 |title=Tilings and Patterns |chapter=Section 2.1: Regular and uniform tilings |publisher=W. H. Freeman and Company |location=New York |year=1987 |pages=59 |doi=10.2307/2323457 |jstor=2323457 |isbn=0-7167-1193-1 |oclc=13092426 |s2cid=119730123 }}</ref>

A regular [[Regular dodecahedron|dodecahedron]] has twelve pentagonal faces. Regular [[Cube|cube]]s and [[Octahedron|octahedron]]s both have 12 edges, while regular [[Icosahedron|icosahedron]]s have 12 vertices. The [[Rhombic dodecahedron|rhombic dodecahedron]] has twelve rhombic faces and is able to tessellate [[Rhombic dodecahedral honeycomb|three-dimensional space]]; it is the only [[Catalan solid]] to generate a honeycomb with copies of itself. Its [[Dual polyhedron|dual polyhedron]], the [[Cuboctahedron|cuboctahedron]], has 12 vertices with radial equilateral symmetry, and is one of two [[Quasiregular polyhedron|quasiregular polyhedra]].

The densest three-dimensional [[Lattice (group)|lattice]] [[Sphere packing|sphere packing]] has each sphere touching twelve other spheres, and this is almost certainly true for ''any'' arrangement of spheres (the [[Kepler conjecture]]). Twelve is also the [[Kissing number|kissing number]] in three dimensions.

There are twelve complex apeirotopes in dimensions five and higher, which include van Oss polytopes in the form of complex <math>n</math>-orthoplexes.<ref>{{Cite book |author=H. S. M. Coxeter |title=Regular Complex Polytopes |publisher=Cambridge University Press |edition=2 |year=1991 |pages=144–146 |doi=10.2307/3617711 |jstor=3617711 |isbn=978-0-521-39490-1 |s2cid=116900933 |zbl=0732.51002 }}</ref> There are also twelve [[Uniform 6-polytope#Regular and uniform hyperbolic honeycombs|paracompact]] hyperbolic [[Coxeter group]]s of uniform polytopes in five-dimensional space.

[[Bring's curve]] is a [[Riemann surface]] of [[Genus (mathematics)|genus]] four, with a domain that is a regular hyperbolic 20-sided [[Icosagon|icosagon]].<ref>{{Cite journal |last=Weber |first=Matthias |url=https://msp.org/pjm/2005/220-1/pjm-v220-n1-p09-s.pdf |title=Kepler's small stellated dodecahedron as a Riemann surface |journal=[[Pacific Journal of Mathematics]] |volume=220 |number=1 |year=2005 |page=172 |doi=10.2140/pjm.2005.220.167 |doi-access=free |mr=2195068 |s2cid=54518859 |zbl=1100.30036 }}</ref> By the Gauss-Bonnet theorem, the area of this [[Fundamental polygon|fundamental polygon]] is equal to <math>12\pi</math>.

The [[Leech lattice]], which holds the solution to the [[Kissing number|kissing number]] in twenty-four dimensions,<ref>{{Cite OEIS |A002336 |Maximal kissing number of n-dimensional laminated lattice. |access-date=2023-04-06 }}
:Equal to 196,560 [[N-sphere|24-spheres]] in twenty-four dimensions.</ref> has a density equal to:
:<math>\frac{\pi^{12}}{12!}\approx 0.00193 \text { }</math><ref>{{Cite journal |last1=Cohn |first1=Henry |last2=Kumar |first2=Abhinav |title=Optimality and uniqueness of the Leech lattice among lattices |journal=[[Annals of Mathematics]] |volume=170 |issue=3 |publisher=[[Organization:Princeton University|Princeton University]] & the Institute for Advanced Study |year=2009 |location=Princeton, NJ |pages=1003–1050 |doi=10.4007/annals.2009.170.1003 |doi-access=free |mr=2600869 |jstor=25662173 |zbl=1213.11144 |s2cid=10696627 }}</ref>

Its [[Quaternion|quaternion]]ic representation contains vectors [[Modular arithmetic|modulo]] <math>1+i</math> that are congruent to either one of <math>1,365 = \tfrac {196,560}{144}</math> [[Frame (linear algebra)|coordinate-frames]], or zero;<ref>{{Cite journal |last=Wilson |first= Robert A. |title=The Quaternionic Lattice for 2G<sub>2</sub>(4) and its Maximal Subgroups |journal=[[Journal of Algebra]] |volume=77 |issue=2 |publisher=[[Company:Elsevier|Elsevier]] |year=1982 |pages=451–453 |doi=10.1016/0021-8693(82)90266-6 |doi-access= |s2cid=120032380 |zbl=0501.20013 |mr=673128 }}</ref><ref>{{Cite journal |last=Allcock |first=Daniel |author-link=Daniel Allcock |title=Orbits in the Leech Lattice |journal=Experimental Mathematics |volume=14 |number=4 |publisher=Taylor & Francis |year=2005 |page=508 |url=https://projecteuclid.org/journals/experimental-mathematics/volume-14/issue-4/Orbits-in-the-Leech-Lattice/em/1136926978.full |doi=10.1080/10586458.2005.10128938 |mr=2193810 |zbl=1152.11334 |s2cid=2883584 }}
:"The reader should note that each of Wilson's frames [Wilson 82] contains three of ours, with 3 · 48 = 144 vectors, and has slightly larger stabilizer."</ref> with 1,365 the twelfth [[Jacobsthal number]], and [[144 (number)|144]] equal to 12<sup>2</sup>.

[[Fischer group]] <math>\mathrm {Fi_{22}}</math> is a [[Sporadic group|sporadic group]] with a total of twelve [[Maximal subgroup|maximal subgroup]]s, the smallest of which is [[Mathieu group]] <math>\mathrm {M_{12}}</math>.<ref>{{Cite journal |last1=Wilson |first1=Robert A. |title=On maximal subgroups of the Fischer group Fi<sub>22</sub> |doi=10.1017/S0305004100061491 |mr=735364  |year=1984 |journal=Mathematical Proceedings of the Cambridge Philosophical Society |issn=0305-0041 |volume=95 |issue=2 |pages=197–222}}</ref><ref>{{Cite web |last1=Wilson |first1=R.A. |last2=Parker |first2=R.A. |last3=Nickerson |first3=S.J. |last4=Bray |first4=J.N. |title=ATLAS: Fischer group Fi22 |url=https://brauer.maths.qmul.ac.uk/Atlas/v3/spor/F22/ |website=ATLAS of Finite Group Representations |year=1999 }}</ref> <math>\mathrm {Fi_{22}}</math> holds [[Generator (mathematics)|standard generators]] <math>(a,b,ab)</math> equal to (2A, 13, 11),<ref>{{Cite journal |last1=Nickerson |first1=S.J. |last2=Wilson |first2=R.A. |author2-link=Robert Anton Wilson |title=Semi-Presentations for the Sporadic Simple Groups |url=https://www.tandfonline.com/doi/abs/10.1080/10586458.2005.10128927 |journal=Experimental Mathematics |volume=14 |issue=3 |page=359−371 |publisher=Taylor & Francis |year=2011 |location=Oxfordshire |doi=10.1080/10586458.2005.10128927 |mr=2172713 |zbl=1087.20025 |s2cid=13100616 }}</ref> with a ''further condition'' where <math>o\bigl((ab)^2 (abab^2)^2 ab^2\bigr) = 12</math>.<ref name=furtherC>{{Cite book |last=Wilson |first=R.A |title=The Atlas of Finite Groups - Ten Years On (LMS Lecture Note Series 249) |chapter=Chapter: An Atlas of Sporadic Group Representations |chapter-url=https://webspace.maths.qmul.ac.uk/r.a.wilson/pubs_files/ASGRweb.pdf|publisher=Cambridge University Press |location=Cambridge, U.K |year=1998 |page=261–273 |doi=10.1017/CBO9780511565830.024 |isbn=9780511565830 |oclc=726827806 |zbl=0914.20016 |s2cid=59394831 }}</ref> Furthermore, its [[Faithful representation|faithful complex representation]] is 78-dimensional,<ref>{{Cite journal |last=Jansen |first=Christoph |date=2005 |title=The Minimal Degrees of Faithful Representations of the Sporadic Simple Groups and their Covering Groups |journal=[[LMS Journal of Computation and Mathematics]] |volume=8 |pages=122−144 |publisher=London Mathematical Society |doi=10.1112/S1461157000000930 |doi-access=free |s2cid=121362819 |zbl=1089.20006 |mr=2153793 }}</ref> where 78 is the twelfth [[Triangular number|triangular number]].<ref>{{Cite OEIS |A000217 |Triangular numbers: a(n) is binomial(n+1,2) equal to n*(n+1)/2, in-turn 0 + 1 + 2 + ... + n. |access-date=2023-07-31 }}</ref> Otherwise, the largest [[Alternating group|alternating group]] represented inside any sporadic groups is <math>\mathrm A_{12}</math>, as a maximal subgroup inside the third-largest [[Sporadic group#Organization|third generation]] sporadic group, Harada-Norton group <math>\mathrm {HN}</math>.<ref>{{Cite journal |last1=Norton |first1=S. P. |last2=Wilson |first2=Robert A. |title=Maximal subgroups of the Harada-Norton group |doi=10.1016/0021-8693(86)90192-4 |mr=860712 |year=1986 |journal=[[Journal of Algebra]] |issn=0021-8693 |volume=103 |issue=1 |pages=362–376|doi-access=free }}</ref><ref>{{Cite web |last1=Wilson |first1=R.A. |author1-link=Robert Arnott Wilson |last2=Parker |first2=R.A. |author2-link=Richard A. Parker |last3=Nickerson |first3=S.J. |last4=Bray |first4=J.N. |title=ATLAS: Harada-Norton group HN |url=https://brauer.maths.qmul.ac.uk/Atlas/v3/spor/HN/ |website=ATLAS of Finite Group Representations |year=1999 }}</ref> While <math>\mathrm {Fi_{22}}</math> or <math>\mathrm A_{12}</math> are not maximal subgroups of the largest sporadic group, the [[Monster group|friendly giant]] <math>\mathrm {F_{1}}</math>, one of its maximal subgroup is <math>(\mathrm {A_{5}} \times \mathrm {A_{12}}):2</math>.<ref name=maxF1>{{Cite web |last1=Wilson |first1=R.A. |author1-link=Robert Arnott Wilson |last2=Parker |first2=R.A. |author2-link=Richard A. Parker |last3=Nickerson |first3=S.J. |last4=Bray |first4=J.N. |title=ATLAS: Monster group M  |url=https://brauer.maths.qmul.ac.uk/Atlas/v3/spor/M/ |website=ATLAS of Finite Group Representations |year=1999 }}</ref> More deeply, the double cover <math>2.\mathrm {Fi_{22}}</math> is a maximal subgroup of <math>\mathrm {Fi_{23}}</math>,<ref>{{Cite journal |last2=Parker |first2=Richard A. |last1=Kleidman |first1=Peter B. |last3=Wilson |first3=Robert A. |title=The maximal subgroups of the Fischer group Fi₂₃ |doi=10.1112/jlms/s2-39.1.89 |mr=989922  |year=1989 |journal=Journal of the London Mathematical Society |series=Second Series |issn=0024-6107 |volume=39 |issue=1 |pages=89–101}}</ref><ref>{{Cite web |last1=Wilson |first1=R.A. |author1-link=Robert Arnott Wilson |last2=Parker |first2=R.A. |author2-link=Richard A. Parker |last3=Nickerson |first3=S.J. |last4=Bray |first4=J.N. |title=ATLAS: Fischer group Fi23 |url=https://brauer.maths.qmul.ac.uk/Atlas/v3/spor/F23/ |website=ATLAS of Finite Group Representations |year=1999 }}</ref> which is the third-largest maximal subgroup inside <math>\mathrm B</math>;<ref>{{Cite journal |last1=Wilson |first1=Robert A. |author-link1=Robert A. Wilson (mathematician) |title=The maximal subgroups of the Baby Monster. I |doi=10.1006/jabr.1998.7601 |mr=1656568 |year=1999 |journal=[[Journal of Algebra]] |volume=211 |issue=1 |pages=1–14|doi-access=free }}</ref><ref>{{Cite web |last1=Wilson |first1=R.A. |author1-link=Robert Arnott Wilson |last2=Parker |first2=R.A. |author2-link=Richard A. Parker |last3=Nickerson |first3=S.J. |last4=Bray |first4=J.N. |title=ATLAS: Baby Monster group B  |url=https://brauer.maths.qmul.ac.uk/Atlas/v3/spor/B/ |website=ATLAS of Finite Group Representations |year=1999 }}</ref> with the double cover <math>2.\mathrm B</math> as the largest maximal subgroup inside <math>\mathrm {F_{1}}</math>.<ref name=maxF1 /> The smallest [[Sporadic group#Organization|second generation]] sporadic group, [[Janko group]] <math>\mathrm {J_{2}}</math>, holds standard generators (2A, 3B, 7) that yield <math>o\bigl([a,b]\bigr) = 12</math>.<ref name=furtherC />

Twelve is the smallest weight for which a [[Cusp form|cusp form]] exists. This cusp form is the discriminant <math>\Delta(q)</math> whose Fourier coefficients are given by the Ramanujan <math>\tau</math>-function and which is (up to a constant multiplier) the 24th power of the [[Dedekind eta function]]: 
:<math>\Delta(\tau)=(2\pi)^{12}\eta^{24}(\tau)</math>
This fact is related to a constellation of interesting appearances of the number twelve in mathematics ranging from the fact that the [[Commutator subgroup#Abelianization|abelianization]] of [[Special linear group|special linear group]] <math>\operatorname{SL}(2,\mathrm {Z})</math> has twelve elements, to the value of the [[Riemann zeta function]] at <math>-1</math> being <math>-\tfrac {1}{12}</math>, which stems from the [[Ramanujan summation]]
:<math> 1 + 2 + 3 + 4 + \cdots=-\frac{1}{12} \quad (\mathfrak{R})</math>

Although the series is divergent, methods such as Ramanujan summation can assign finite values to divergent series.

*12 is an Anti-Meertens Number. If we power the digits from the end to the prime numbers starting from 2 and then multiply, then the result will be the number Itself.

2^2 * 3^1 = 12

===List of basic calculations===

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|'''12 × ''x'''''
|'''12'''
|[[24 (number)|24]]
|[[36 (number)|36]]
|[[48 (number)|48]]
|[[60 (number)|60]]
|[[72 (number)|72]]
|[[84 (number)|84]]
|[[96 (number)|96]]
|[[108 (number)|108]]
|[[120 (number)|120]]
|[[132 (number)|132]]
|[[144 (number)|144]]
|[[156 (number)|156]]
|[[168 (number)|168]]
|[[180 (number)|180]]
|[[192 (number)|192]]
|[[204 (number)|204]]
|[[216 (number)|216]]
|[[228 (number)|228]]
|[[240 (number)|240]]
|[[252 (number)|252]]
|[[264 (number)|264]]
|[[276 (number)|276]]
|[[288 (number)|288]]
|[[300 (number)|300]]
!
|[[600 (number)|600]]
|1200
|12000
|}

{|class="wikitable" style="text-align: center; background: white"
|-
! style="width:105px;"|[[Division (mathematics)|Division]]
!1
!2
!3
!4
!5
!6
!7
!8
!9
!10
! style="width:5px;"|
!11
!12
!13
!14
!15
!16
|-
|'''12 ÷ ''x'''''
|'''12'''
|6
|4
|3
|2.4
|2
|1.{{overline|714285}}
|1.5
|1.{{overline|3}}
|1.2
!
|1.{{overline|09}}
|1
|0.{{overline|923076}}
|0.{{overline|857142}}
|0.8
|0.75
|-
|'''''x'' ÷ 12'''
|0.08{{overline|3}}
|0.1{{overline|6}}
|0.25
|0.{{overline|3}}
|0.41{{overline|6}}
|0.5
|0.58{{overline|3}}
|0.{{overline|6}}
|0.75
|0.8{{overline|3}}
!
|0.91{{overline|6}}
|1
|1.08{{overline|3}}
|1.1{{overline|6}}
|1.25
|1.{{overline|3}}
|}

{|class="wikitable" style="text-align: center; background: white"
|-
!width="105px"|[[Exponentiation]]
!1
!2
!3
!4
!5
!6
!7
!8
!9
!10
!width="5px"|
!11
!12
|-
|'''12{{sup|''x''}}'''
|'''12'''
|144
|1728
|20736
|248832
|2985984
|35831808
|429981696
|5159780352
|61917364224
!
|743008370688
|8916100448256
|-
|'''''x''{{sup|12}}'''
|1
|4096
|531441
|16777216
|244140625
|2176782336
|13841287201
|68719476736
|282429536481
|1000000000000 
!
|3138428376721
|8916100448256
|}

====In other bases====

The [[Duodecimal|duodecimal]] system (12<sub>10</sub> [twelve] =&nbsp;10<sub>12</sub>), which is the use of 12 as a division factor for many ancient and [[Medieval weights and measures|medieval weights and measures]], including [[Hour|hour]]s, probably originates from [[Place:Mesopotamia|Mesopotamia]].

In base thirteen and higher bases (such as [[Hexadecimal|hexadecimal]]), twelve is represented as C.

==In nature==
Notably, twelve is the number of full lunations in a solar year, hence the number of months in a solar calendar, as well as the number of signs in the [[Unsolved:Western astrology|Western]], Islamic and the [[Philosophy:Chinese astrology|Chinese]] [[Astronomy:Zodiac|zodiac]]. Twelve is also the number of [[Astronomy:Jupiter#Pre-telescopic research|years for an orbital period of Jupiter]].

==Religion==
The number twelve carries religious, mythological and magical [[Symbol|symbol]]ism, generally representing perfection, entirety, or cosmic order in traditions since antiquity.{{sfnp|Drews|1972|loc=p. 43, n. 10}}

=== Ancient Greek religion ===
*The Twelve Olympians are the principal gods of the pantheon, they were preceded by twelve Titans, and [[Religion:Hercules|Hercules]] carries out twelve labours.<ref>{{citation |last=Weinreich |first=Th. |contribution=Zwölfgötter |editor-last=Roscher |editor-first=W.H. |display-editors=0 |title=Ausführliches Lexikon der Griechischen und Römischen Mythologie |volume=VI |at=col. 764-848 }}.</ref> 
*Several sets of twelve cities are identified in history as a dodecapolis, the most familiar being the Etruscan League. In ancient Rome, the twelve lictors carried [[Fasces|fasces]] of twelve rods.

=== Judaism and Christianity ===
* The significance is especially pronounced in the [[Religion:Hebrew Bible|Hebrew Bible]].
Ishmael – the first-born son of [[Biography:Abraham|Abraham]] – has 12 sons/princes (Genesis 25:16), and Jacob also has 12 sons, who are the progenitors of the Twelve Tribes of Israel.<ref>"And it is thought that there is a special significance in the number twelve. It was typified, we know, by many things in the Old Testament; by the twelve sons of Jacob, by the twelve princes of the children of Israel, by the twelve fountains in Elim, by the twelve stones in Aaron's breast-plate, by the twelve loaves of the shew-bread, by the twelve spies sent by Moses, by the twelve stones of which the altar was made, by the twelve stones taken out of Jordan, by the twelve oxen which bare"
P. Young, ''Daily readings for a year'' (1863), [https://books.google.com/books?id=fZgEAAAAQAAJ&pg=PA150  p. 150].
</ref> This is reflected in Christian tradition, notably in the twelve Apostles. When Judas Iscariot is disgraced, a meeting is held (Acts) to add Saint Matthias to complete the number twelve once more.
The [[Religion:Book of Revelation|Book of Revelation]] contains much numerical symbolism, and many of the numbers mentioned have 12 as a divisor. {{Bibleverse-nb||Revelation|12:1|31}} mentions a woman&mdash;interpreted as the people of Israel, the Church and the Virgin Mary&mdash;wearing a crown of twelve stars (representing each of the twelve tribes of Israel). Furthermore, there are 12,000 people sealed from each of the twelve tribes of Israel (the Tribe of Dan is omitted while Manasseh is mentioned), making a total of 144,000 (which is the square of 12 multiplied by a thousand).
* According to the New Testament, Jesus had twelve Apostles.
* The "Twelve Days of Christmas" count the interval between Christmas and Epiphany. 
* Eastern Orthodoxy observes twelve Great Feasts.

12 was the only number considered to be religiously divine in the 1600s causing many Catholics to wear 12 buttons to church every Sunday. Some extremely devout Catholics would always wear this number of buttons to any occasion on any type of clothing.{{citation needed|date=June 2023}}

=== Islam ===
Twelve is referred to in three different [[Religion:Āyah|verses]] of the [[Religion:Quran|Quran]]. Two are in reference to the Twelve Tribes of Israel.

{{blockquote|And ˹remember˺ when Moses prayed for water for his people, We said, "Strike the rock with your staff." Then twelve springs gushed out, ˹and˺ each tribe knew its drinking place. ˹We then said,˺ "Eat and drink of Allah’s provisions, and do not go about spreading corruption in the land."|[[Religion:Surah|Surah]] ''Al-Baqarah'' (The Heifer):60<ref>{{Cite web |title=Surah Al-Baqarah - 60 |url=https://quran.com/al-baqarah/60 |access-date=2023-08-02 |website=Quran.com |language=en}}</ref>}}

The second reference is:
{{blockquote|We divided them into twelve tribes—each as a community. And We revealed to Moses, when his people asked for water, "Strike the rock with your staff." Then twelve springs gushed out. Each tribe knew its drinking place. We shaded them with clouds and sent down to them manna and quails,<sup>1</sup> ˹saying˺, "Eat from the good things We have provided for you." They ˹certainly˺ did not wrong Us, but wronged themselves.|Surah ''Al-A'raf'' (The Heights):160<ref>{{Cite web |title=Surah Al-A'raf - 160 |url=https://quran.com/al-araf/160 |access-date=2023-08-02 |website=Quran.com |language=en}}</ref>}}

Note 1: Manna (heavenly bread) and quails (chicken-like birds) sustained the children of Israel in the wilderness after they left Egypt.

The last reference is to the number of months and the sacred ones amongst them:
{{blockquote|Indeed, the number of months with Allāh is twelve [lunar] months in the register of Allāh [from] the day He created the heavens and the earth; of these, four are sacred.<sup>2</sup>|Surah ''At-Tawbah'' (The Repentance):36<ref>{{Cite web |title=Surah At-Tawbah - 36 |url=https://quran.com/at-tawbah/36 |access-date=2023-08-02 |website=Quran.com |language=en}}</ref>}}

Note 2: The four sacred months of the [[Engineering:Islamic calendar|Islamic calendar]] are [[Religion:Dhu al-Qadah|Dhu al-Qa'dah]], [[Religion:Dhu al-Hijja|Dhu al-Hijja]]h, [[Religion:Muharram|Muharram]], and [[Religion:Rajab|Rajab]] (months 11, 12, 1 and 7).

=== Hinduism ===
* There are twelve Jyotirlinga (''Self-formed Lingas'') of Lord [[Religion:Shiva|Shiva]] in Hindu temples across {{wipe|India}} according to the Shaiva tradition.
* The Sun god [[Religion:Surya|Surya]] has 12 names.
* The god Hanuman has 12 names.
* There are 12 Petals in [[Philosophy:Anahata|Anahata]] or "heart chakra".
* There are frequently said to be 12 Âdityas.

=== Others ===
[[File:Yazilikaya_B_12erGruppe.jpg|thumb|Ancient [[History:Hittites|Hittite]] relief carving from Yazılıkaya, a sanctuary at Hattusa, depicting twelve gods of the underworld{{sfn|Collins|2002|page=[https://books.google.com/books?id=xMDHgzjSU_MC&pg=PA228 228]}}]]
* The chief Norse god, [[Religion:Odin|Odin]], has twelve sons.{{Citation needed|date=September 2021}}
* In the King Arthur [[Social:Legend|legend]], Arthur is said to subdue 12 rebel princes and to win 12 great battles against Saxon invaders.<ref>Benet's Reader's Encyclopedia, 3d ed.</ref>  
* In [[Religion:Twelver|Twelver]] [[Religion:Shia Islam|Shi'a Islam]], there are twelve Imams, legitimate successors of the Islamic prophet, [[Biography:Muhammad|Muhammad]]. These twelve early leaders of Islam are&mdash;Ali, [[Religion:Hasan ibn Ali|Hasan]], [[Biography:Husayn ibn Ali|Husayn]], and nine of Husayn's descendants. Sura 12 in the [[Religion:Quran|Quran]] is sura Yusuf, narrating the story of the sons of Jacob.
* In the mythologies of the ancient Hurrians and [[History:Hittites|Hittites]], there were the [[Unsolved:Anunnaki#Hurrian and Hittite|Twelve gods of the Underworld]].

==Law==

* The number of twelve jurors in jury trials is depicted by [[Biography:Aeschylus|Aeschylus]] in the ''Eumenides''. In the play, the innovation is brought about by the goddess Athena, who summons twelve citizens to sit as jury.
*In English Common Law, the tradition of twelve jurors harks back to the 10th-century law code introduced by Aethelred the Unready.

==Timekeeping==
* The lunar year is 12 lunar months. Adding 11 or 12 days completes the solar year.<ref>{{cite web|title=Lunar versus solar calendar|url=http://www.ghazali.net/calander/Linar_v_Solar/linar_v_solar.html}}</ref> 
* Most [[Physics:Calendar|calendar systems]] – solar or lunar – have twelve months in a [[Year|year]].
* The Chinese use a 12-year cycle for time-reckoning called [[Unsolved:Earthly Branches|Earthly Branches]].
* There are twelve [[Hour|hour]]s in a half day, numbered one to twelve for both the ''ante meridiem'' (a.m.) and the ''post meridiem'' (p.m.). 12:00&nbsp;p.m. is midday or [[Astronomy:Noon|noon]], and 12:00&nbsp;a.m. is midnight. 
* The basic units of time (60 seconds, 60 minutes, 24 hours) are evenly divisible by twelve into smaller units.

==In numeral systems==
<!-- см. -->
{| class="wikitable"
!style="font-size:2em;line-height:1.0;font-family:Arial Unicode MS, Code2000,serif"|{{lang|ar|۱۲}}
| [[Arabic numerals|Arabic]]
!style="font-size:2em;line-height:1.0;font-family:Arial Unicode MS, Code2000,serif"|{{lang|ar|១២}}
| [[Khmer numerals|Khmer]]

!style="font-size:2em;line-height:1.0;font-family:Arial Unicode MS, Code2000,serif"|{{lang|hy|ԺԲ}}
| [[Armenian numerals|Armenian]]
|-
!style="font-size:2em;line-height:1.0;font-family:Arial Unicode MS, Code2000,serif"|{{lang|ar|১২}}
| Bangla

!style="font-size:2em;line-height:1.0;font-family:Arial Unicode MS, Code2000,serif"| {{lang|el|ΔΙΙ}}
| [[Attic numerals|Attic]] [[Greek numerals|Greek]]

!style="font-size:2em;line-height:1.0;font-family:Arial Unicode MS, Code2000,serif"| {{lang|el|𝋬}}
| [[Maya numerals|Maya]]
|-
!style="font-size:2em;line-height:1.0;font-family:Arial Unicode MS, Code2000,serif"| {{lang|he|יב}}
| [[Hebrew numerals|Hebrew]]
!style="font-size:2em;line-height:1.0;font-family:Arial Unicode MS, Code2000,serif"|<hiero>V20-Z1-Z1</hiero>
| [[Egyptian numerals|Egyptian]]
|-
!style="font-size:2em;line-height:1.0;font-family:Arial Unicode MS, Code2000,serif"|{{lang|hi|१२}}
| [[Indian numerals|Indian and Nepali]] (Devanāgarī)
!style="font-size:2em;line-height:1.0;font-family:Arial Unicode MS, Code2000,serif"|{{lang|zh|十二}}
| [[Chinese numerals|Chinese]] and [[Japanese numerals|Japanese]]
|-
!style="font-size:2em;line-height:1.0;font-family:Arial Unicode MS, Code2000,serif"|{{lang|ta|௧௨}}
| Tamil
!style="font-size:2em;line-height:1.0;font-family:Arial Unicode MS, Code2000,serif"|{{lang|la|XII}}
| [[Roman numerals|Roman]] and [[Etruscan numerals|Etruscan]]
|-
!style="font-size:2em;line-height:1.0;font-family:Arial Unicode MS, Code2000,serif"|{{lang|th|๑๒}}
| [[Thai numerals|Thai]]
!style="font-size:2em;line-height:1.0;font-family:Arial Unicode MS, Code2000,serif"| {{lang|cv|IIX}}
| [[Social:Chuvash language|Chuvash]]
|-
!style="font-size:2em;line-height:1.0;font-family:Arial Unicode MS, Code2000,serif"|{{lang|te|౧౨}}
| [[Social:Telugu script|Telugu]] and Kannada
!style="font-size:2em;line-height:1.0;font-family:Arial Unicode MS, Code2000,serif"| {{lang|ur|١٢}}
| Urdu
|-
!style="font-size:2em;line-height:1.0;font-family:Arial Unicode MS, Code2000,serif"| {{lang|el|ιβʹ}}
| Ionian [[Greek numerals|Greek]]
!style="font-size:2em;line-height:1.0;font-family:Arial Unicode MS, Code2000,serif"|{{lang|ml|൧൨}}
| [[Thai numerals|Malayalam]]
|}

==In science==
[[File:Messier 12 Hubble WikiSky.jpg|thumb|Image of the globular cluster Messier 12 by Hubble Space Telescope]]
*The [[Physics:Atomic number|atomic number]] of [[Chemistry:Magnesium|magnesium]] in the [[Chemistry:Periodic table|periodic table]].
*The [[Physics:Standard Model|Standard Model]] identifies twelve types of elementary [[Physics:Fermion|fermion]]s as well as twelve types of elementary [[Physics:Gauge boson|gauge boson]]s.
*The human body has twelve cranial nerves.
*The [[Biology:Duodenum|duodenum]] (from {{Lang-la|duodecim|lit=twelve}}) is the first part of the [[Biology:Small intestine|small intestine]], that is about twelve inches (30&nbsp;cm) long. More precisely, this section of the intestine was measured not in inches but in fingerwidths. In fact, in [[Social:German language|German]] the name of the duodenum is {{Lang|de|Zwölffingerdarm}}, in [[Social:Dutch language|Dutch]] the name is ''{{Lang|nl|twaalfvingerige darm}}'' and in [[Social:Bulgarian language|Bulgarian]] the name is {{Lang|bg|дванадесетопръстник}}, all meaning "twelve-finger bowel".
*Force 12 on the Beaufort wind force scale corresponds to the maximum wind speed of a hurricane.
*The human body has twelve thoracic vertebrae.
*[[Astronomy:Messier 12|Messier 12]] (NGC 6218), an [[Astronomy:Globular cluster|globular cluster]] in the constellation [[Astronomy:Ophiuchus|Ophiuchus]], located at 16,400 light years away from earth

==In sports==
* In both soccer and American football, the number 12 can be a symbolic reference to the fans because of the support they give to the 11 players on the field. Texas A&M University reserves the number 12 jersey for a walk-on player who represents the original "12th Man", a fan who was asked to play when the team's reserves were low in a college American football game in 1922. Similarly, Bayern Munich, Hammarby, Feyenoord, Atlético Mineiro, Flamengo, Seattle Seahawks, Portsmouth and Cork City do not allow field players to wear the number 12 on their jersey because it is reserved for their supporters. It also serves as the jersey number for some the National Football League's best and most well-known quarterback, Tom Brady.
* In Canadian football, 12 is the maximum number of players that can be on the field of play for each team at any time.
* In cricket, another sport with eleven players per team, teams may select a "12th man", who may replace an injured player for the purpose of fielding (but not batting or bowling).
* In women's lacrosse, each team has 12 players on the field at any given time, except in penalty situations.
* In rugby league, one of the starting second-row forwards wears the number 12 jersey in most competitions. An exception is in the Super League, which uses static squad numbering.
* In rugby union, one of the starting centres, most often but not always the inside centre, wears the 12 shirt.
* In an NBA game, a quarter lasts 12 minutes.
* In pool:
** The pool ball 12 is the 12th in pool and its color is purple.

==In technology==
*[[ASCII]] and [[Unicode]] code point for form feed.
* The number of function keys on most PC keyboards (F1 through F12). 
* The number of keys in any standard digital telephone (1 through 9, 0, * and #). 
* Microsoft's [[Rich Text Format]] specification assigns numbers congruent to 12 mod 256 to variants of the [[Social:French language|French language]].

==In the arts==

===Film===
Films with the number twelve or its variations in their titles include: 
*''12''
*''12 Angry Men'' (1957 and 1997)
*''Cheaper by the Dozen''
*''Ocean's Twelve''
*''12 Monkeys''
*''The Dirty Dozen''
*''The Twelve Chairs'' (1970, 1971 and 1976)
*''12 Rounds''
*''Twelve''
*''Twelve Years a Slave''

===Television===
*The number twelve plays a significant role in the television franchise ''Battlestar Galactica''. The characters come from the Twelve Colonies of Kobol and worship the twelve gods of Kobol. In the re-imagined series, there are also twelve models of humanoid Cylons.
*''Twelve Angry Men'', the original 1954 live performance on the anthology television series ''Studio One''
*"Number 12 Looks Just Like You" is an episode of the television show ''The Twilight Zone''.
*''Schoolhouse Rock!'' portrayed an alien child using [[Duodecimal|base-twelve]] arithmetic in the short "Little Twelvetoes".
*''12 oz. Mouse'' was an animated television show on Adult Swim.
* The News 12 Networks are a group of American regional cable news television channels covering New York, New Jersey, and Connecticut.
* ''{{ill|Les Douze Coups de Midi|fr}}'' ({{Lang|fr|douze}} = 12) is a French game show broadcast on TF1 with Jean-Luc Reichmann at midday CEST.
* In ''Star Twinkle PreCure'', the Star Palace is home to the twelve Star Princesses, one for each sign of the Zodiac.

===Theatre===
* ''Twelfth Night'' is a comedy by William Shakespeare. 
* ''The Vision of the Twelve Goddesses'' is a Jacobean masque by Samuel Daniel. 
* ''Twelve Angry Men'', by Reginald Rose, adapted from his own teleplay (see above).

===Literature===
* "The Twelve" is a poem by Aleksandr Blok. 
* ''Twelve'' is a novel by Nick McDonell. 
* ''The Twelve Chairs'' is a satirical novel by the Soviet authors Ilf and Petrov. 
* ''Cheaper by the Dozen'' is a 1946 novel by Frank Bunker Gilbreth Jr. and Ernestine Gilbreth Carey. 
* ''The Twelve Dancing Princesses'' is a folk tale. 
* The ''Aeneid'', an epic poem by ''Virgil'' is divided into two halves composed of twelve books.
* ''[[Astronomy:Paradise Lost|Paradise Lost]]'', an epic poem by ''[[Biography:John Milton|John Milton]]'' is divided into twelve books perhaps in imitation of the ''Aeneid''. 
* Miguel de Cervantes wrote twelve ''Novelas ejemplares''.
* The number twelve is a key feature in the plot of the novel ''Murder on the Orient Express'' by Agatha Christie.

===Music===
====Music theory====
*Twelve is the number of pitch classes in an octave, not counting the duplicated (octave) pitch. Also, the total number of major keys, (not counting enharmonic equivalents) and the total number of minor keys (also not counting equivalents). This applies only to twelve tone equal temperament, the most common tuning used today in western influenced music.
*The twelfth is the interval of an octave and a fifth. Instruments such as the [[Engineering:Clarinet|clarinet]] which behave as a stopped cylindrical pipe overblow at the twelfth.
*The twelve-tone technique (also dodecaphony) is a method of musical composition devised by Arnold Schoenberg. Music using the technique is called twelve-tone music.
*The twelve-bar blues is one of the most prominent chord progressions in popular music.
*12-inch phonograph record.

====Pop music====

* The 12-inch single is a vinyl record format.
*Twelfth Night is a progressive rock band. 
*''12 Play'' is an R. Kelly album.
*The Number 12 Looks Like You is a mathcore band.
*"12", a song from the album ''Brave Murder Day'' by Katatonia.
*''12'' is a studio album by German singer Herbert Grönemeyer.
*''Twelve'' is an album by Patti Smith.
*''Twelve Deadly Cyns...and Then Some'' is an album by Cyndi Lauper.
*D12 a rap group also known as the Dirty Dozen.
*12 Stones is an American Christian rock band. 
*"12 Hundred" is a song by band Mushroomhead of their ''Savior Sorrow'' album.
*''12'' is the 12th studio album by Keller Williams.
*"12" ("Dodeka" in Greek) is one of the most well-known hits by Anna Vissi. 
*"Twelve drummers drumming" is the gift on the twelfth day of Christmas in the carol "The Twelve Days of Christmas". 
*Twelve Girls Band are an all female Chinese musical group . 
*''12 (American Song Book)'' is an album by Italian singer Mina. 
*"Revelation #12" is a song by American rock band Marilyn Manson.
* 12 is the maximum score a competing entry can receive by each country in the Eurovision Song Contest.

===Art theory===
* There are twelve basic hues in the color wheel: three primary colors (red, yellow, blue), three secondary colors (orange, green, purple) and six tertiary colors (names for these vary, but are intermediates between the primaries and secondaries).

===Games===
* In the game of craps, a dice roll of two sixes (value 12) on the come-out roll constitutes a "craps" and the shooter (dice thrower) loses immediately.
* Twelve is a character in the ''[[Software:Street Fighter|Street Fighter]]'' video game series.
* Games such as Backgammon have a long history of 12 points on each side of the gaming board, as evidenced in the XII scripta board in the museum at Ephesus.<ref>{{Cite web|last=Attia|first=Peter|date=2018-09-05|title=The Full History of Board Games|url=https://medium.com/@peterattia/the-full-history-of-board-games-5e622811ce89|access-date=2020-10-22|website=Medium|language=en}}</ref>

==In other fields==
[[File:Flag of Europe.svg|150px|thumb|12 stars are featured on the Flag of Europe.]]
* There are 12 troy ounces in a [[Troy weight|troy pound]] (used for precious metals).
* Twelve of something is called a [[Dozen|dozen]].
* In the former British currency system, there were twelve pence in a shilling.<ref>{{cite web |title=Shilling {{!}} currency |url=https://www.britannica.com/topic/shilling |website=Encyclopedia Britannica |access-date=20 May 2021 |language=en}}</ref>
* In [[Religion:Greek mythology|Greek mythology]], the number of Labours of Heracles was increased from ten to make twelve.
* In English, twelve is the number of greatest magnitude that has just one syllable.[[File:Animated analog SVG clock.svg|150px|thumb|The numerical range on the analog clock ends at 12.]]
* 12 is the last number featured on the analogue clock, and also the starting point of the transition from A.M. to P.M. hours or vice-versa.
* There are twelve months within a year, with the last one being December.
* The level of grades in which one must attend school typically ends at 12 (although some jurisdictions may include a thirteenth grade depending on the country).{{citation needed|date=January 2021}}
* Twelve hours form half a day, and twelve hours away from another lead to the same time but with a different period (ex. Twelve hours away from 6:00 AM leads to 6:00 PM).
* There are normally twelve pairs of [[Biology:Rib|rib]]s in the human body.
* The ''Twelve Tables'' or ''Leges Duodecim Tabularum'', more informally simply ''Duodecim Tabulae'', was the ancient legislation underlying Roman law.
* In the {{wipe|United States}}, twelve people are appointed to sit on a jury for felony trials in all but four states, and in federal and [[Place:Washington, D.C.|Washington, D.C.]] courts. The number of jurors gave the title to the play (and subsequent films) ''Twelve Angry Men''.
* Twelve men have [[Astronomy:List of Apollo astronauts#Apollo astronauts who walked on the Moon|walked on Earth's moon]].
* The United States is divided into twelve [[Finance:Federal Reserve|Federal Reserve]] Districts (Boston, New York, Philadelphia, Cleveland, Richmond, Atlanta, Chicago, St. Louis, Minneapolis, Kansas City, Dallas, and San Francisco); American paper currency has serial numbers beginning with one of twelve different letters, A through L, representing the Federal Reserve Bank from which the currency originated.
* According to [[Unsolved:UFO conspiracy theory|UFO conspiracy theory]], [[Unsolved:Majestic 12|Majestic 12]] is a secret committee, allegedly set up by U.S. President Harry S. Truman to investigate the Roswell UFO incident and cover up future extraterrestrial contact.
* 12 is the number of the French department Aveyron.
* King Arthur's Round Table had 12 knights plus King Arthur himself.
* 12 inches in a foot.
* Alcoholics Anonymous has 12 steps, 12 traditions and 12 concepts for world service.
* Wilhelm Heinrich Schüßler developed a list of 12 biochemical cell salts, also known as tissue salts.
* In the People's Republic of China, 12 [[Social:Core Socialist Values|Core Socialist Values]] were promoted as part of a campaign beginning in 2012.

== See also ==
* The Twelfth

== Notes ==
{{NoteFoot}}

== References ==
{{Reflist}}

==Sources ==

* {{citation|last=Collins|first=Billie Jean|date=2002|article=Necromancy, Fertility and the Dark Earth: The Use of Ritual Pits in Hittite Cult|url=https://books.google.com/books?id=xMDHgzjSU_MC&q=Hittite+underworld+deities&pg=PA224|title=Magic and Ritual in the Ancient World|pages=224–233|editor1-last=Mirecki|editor1-first=Paul|editor2-last=Meyer|editor2-first=Marvin|location=Leiden, The Netherlands|publisher=Brill|isbn=90-04-10406-2}}
* {{cite journal |last = Drews |first = Robert |title = Light from Anatolia on the Roman Fasces |journal = The American Journal of Philology |volume = 93 |number = 1 |date = January 1972 |pages = 40–51 |doi = 10.2307/292899 |jstor = 292899 }}.

==Further reading==
===Books===
* {{cite book |first = Steven |last = Schwartzman |title = The words of mathematics: An etymological dictionary of mathematical terms used in English |url = https://archive.org/details/wordsofmathemati0000schw |url-access = registration |publisher = The Mathematical Association of America |year = 1994 |isbn = 0-88385-511-9 }}

===Journal articles===
* {{cite journal |title = Lattice Polygons and the Number 12 |first1 = Bjorn |last1 = Poonen |first2 = Fernando |last2 = Rodriguez-Villegas |journal = American Mathematical Monthly |volume = 107 |number = 3 |date = March 2000 |pages = 238–250 |doi = 10.1080/00029890.2000.12005186 |s2cid = 11433945 |url = http://www.math.utexas.edu/users/villegas/publications/polygons.pdf |archive-url = https://web.archive.org/web/20120414212259/http://www.math.utexas.edu/users/villegas/publications/polygons.pdf |url-status = dead |archive-date = 2012-04-14 }}

== External links ==

{{Clear}}

{{DEFAULTSORT:12 (Number)}}
[[Category:Integers]]
[[Category:Numerology]]

{{Sourceattribution|12 (number)}}