View source for 3

{{Short description|Integer number 3}}
{{Hatnote|This article is about the number. For the years, see [[3 BC]] and [[AD 3]]. For other uses, see [[3 (disambiguation)]], [[III (disambiguation)]] and [[Number Three (disambiguation)]].}}
{{Distinguish|Ze (Cyrillic){{!}}З (ze)|Ezh{{!}}Ʒ (ezh)|Yogh{{!}}Ȝ (yogh)|ayin{{!}}ع (ʿayn)}}
{{technical reasons|:3|the keyboard symbols|List of emoticons}}

{{Infobox number
|number=3
|numeral=[[Ternary numeral system|ternary]]
|factorization=[[prime number|prime]]
|prime=2nd
|divisor=1, 3
|roman =III, iii
|greek prefix=[[wikt:tri-|tri-]]
|latin prefix=[[wikt:tre-|tre-]]/[[wikt:ter-|ter-]]
|lang1=[[Eastern Arabic numerals|Arabic]], [[Central Kurdish|Kurdish]], [[Persian language|Persian]], [[Sindhi language|Sindhi]], [[Urdu numerals|Urdu]]
|lang1 symbol={{resize|150%|٣}}
|lang2=[[Bengali language|Bengali]], [[Assamese language|Assamese]]
|lang2 symbol={{resize|150%|৩}}
|lang3=[[Chinese numeral|Chinese]]
|lang3 symbol=三，弎，叄
|lang4=[[Devanāgarī]]
|lang4 symbol={{resize|150%|३}}
|lang5=[[Ge'ez alphabet|Ge'ez]]
|lang5 symbol=፫
|lang6=[[Greek numerals|Greek]]
|lang6 symbol=γ (or Γ)
|lang7=[[Hebrew numerals|Hebrew]]
|lang7 symbol={{resize|150%|ג}}
|lang8=[[Japanese numerals|Japanese]]
|lang8 symbol=三/参
|lang9=[[Khmer numerals|Khmer]]
|lang9 symbol={{resize|150%|៣}}
|lang10=[[Armenian numerals|Armenian]]|lang10 symbol=Գ|lang11=[[Malayalam language|Malayalam]]
|lang11 symbol={{resize|150%|൩}}
|lang12=[[Tamil language|Tamil]]
|lang12 symbol={{resize|150%|௩}}
|lang13=[[Telugu language|Telugu]]
|lang13 symbol={{resize|150%|౩}}
|lang14=[[Kannada numerals|Kannada]]
|lang14 symbol={{resize|150%|೩}}
|lang15=[[Thai numerals|Thai]]
|lang15 symbol={{resize|150%|๓}}
|lang16=[[N'Ko script|N'Ko]]
|lang16 symbol={{resize|150%|߃}}
|lang17=[[Lao numerals|Lao]]
|lang17 symbol={{resize|150%|໓}}
|lang18=[[Georgian numerals|Georgian]]
|lang18 symbol={{resize|130%|Ⴂ/ⴂ/გ}} ([[Gani (letter)|Gani]])
|lang19=[[Babylonian cuneiform numerals|Babylonian numeral]]|lang19 symbol=𒐗|lang20=[[Maya numerals]]|lang20 symbol=•••|lang21=[[Morse code]]|lang21 symbol={{resize|150%|... _ _}}}}

'''3''' ('''three''') is a [[number]], [[numeral (linguistics)|numeral]] and [[numerical digit|digit]]. It is the [[natural number]] following [[2]] and preceding [[4]], and is the smallest odd [[prime number]] and the only prime preceding a square number. It has religious and cultural significance in many societies.

==Evolution of the Arabic digit==
[[File:Evolution3glyph.png|x50px|left]]
The use of three lines to denote the number 3 occurred in many writing systems, including some (like Roman and [[Chinese numerals]]) that are still in use. That was also the original representation of 3 in the [[Brahmic numerals|Brahmic]] (Indian) numerical notation, its earliest forms aligned vertically.<ref name="Smith Karpinski 1911">{{cite book |last1=Smith |first1=David Eugene |last2=Karpinski |first2=Louis Charles |author1-link=David Eugene Smith |author2-link=Louis Charles Karpinski |title=The Hindu-Arabic numerals |date=1911 |publisher=Ginn and Company |location=Boston; London |pages=27–29, 40–41 |url=https://archive.org/details/hinduarabicnumer00smitrich/}}</ref> However, during the [[Gupta Empire]] the sign was modified by the addition of a curve on each line. The [[Nāgarī script]] rotated the lines clockwise, so they appeared horizontally, and ended each line with a short downward stroke on the right. In cursive script, the three strokes were eventually connected to form a glyph resembling a {{angbr|3}} with an additional stroke at the bottom: '''३'''. 

The Indian digits spread to the [[Caliphate]] in the 9th century. The bottom stroke was dropped around the 10th century in the western parts of the Caliphate, such as the [[Maghreb]] and [[Al-Andalus]], when a distinct variant ("Western Arabic") of the digit symbols developed, including modern Western 3. In contrast, the Eastern Arabs retained and enlarged that stroke, rotating the digit once more to yield the modern ("Eastern") [[Arabic script|Arabic]] digit "'''٣'''".<ref>Georges Ifrah, ''The Universal History of Numbers: From Prehistory to the Invention of the Computer'' transl. David Bellos et al. London: The Harvill Press (1998): 393, Fig. 24.63</ref>

In most modern Western [[typeface]]s, the digit 3, like the other [[decimal digit]]s, has the height of a [[capital letter]], and sits on the [[baseline (typography)|baseline]]. In typefaces with [[text figures]], on the other hand, the glyph usually has the height of a [[lowercase letter]] "x" and a [[descender]]: "[[File:Text figures 036.svg|50px]]". In some [[French language|French]] text-figure typefaces, though, it has an [[ascender (typography)|ascender]] instead of a descender.

{{anchor|Flat-topped 3}}
A common graphic variant of the digit three has a flat top, similar to the letter [[Ʒ]] (ezh). This form is sometimes used to prevent falsifying a 3 as an 8. It is found on [[Universal Product Code|UPC-A]] barcodes and [[standard 52-card deck]]s.

== Mathematics ==
According to [[Pythagoras]] and the [[Pythagoreanism|Pythagorean]] school, the number 3, which they called ''triad'', is the only number to equal the sum of all the terms below it, and the only number whose sum with those below equals the product of them and itself.<ref>{{citation |author=Priya Hemenway |title=Divine Proportion: Phi In Art, Nature, and Science |pages=53–54 |year=2005 |publisher=Sterling Publishing Company Inc. |isbn=1-4027-3522-7}}</ref>

=== Divisibility rule ===
A [[natural number]] is [[divisible]] by three if the [[digital root|sum of its digits]] in [[base 10]] is divisible by 3. For example, the number 21 is divisible by three (3 times 7) and the sum of its digits is 2 + 1 = 3. Because of this, the reverse of any number that is divisible by three (or indeed, any [[permutation]] of its digits) is also divisible by three. For instance, 1368 and its reverse 8631 are both divisible by three (and so are 1386, 3168, 3186, 3618, etc.). See also [[Divisibility rule]]. This works in [[base 10]] and in any [[positional notation|positional numeral system]] whose [[radix|base]] divided by three leaves a remainder of one (bases 4, 7, 10, etc.).

=== Properties of the number ===
3 is the second smallest [[prime number]] and the first [[Parity (mathematics)|odd]] prime number. It is the first [[unique prime]], such that the [[period length]] value of [[1]] of the [[decimal expansion]] of its [[Multiplicative inverse|reciprocal]], 0.333..., is unique. 3 is a [[twin prime]] with [[5]], and a [[cousin prime]] with [[7]], and the only known number <math>n</math> such that <math>n</math>! − 1 and <math>n</math>! + 1 are prime, as well as the only prime number <math>p</math> such that <math>p</math> − 1 yields another prime number, [[2]] It is a [[largely composite number]],<ref name="OEIS-A067128">{{Cite OEIS|A067128|Ramanujan's largely composite numbers}}</ref> as it (like all primes) has 2 [[divisor]]s and no smaller number has more than 2 divisors (as there is no [[composite number]] less than 3). A [[triangle]] is made of three [[Edge (geometry)|sides]]. It is the smallest non-self-intersecting [[polygon]] and the only polygon not to have proper [[diagonals]]. When doing quick estimates, 3 is a rough approximation of [[pi|{{pi}}]], 3.1415..., and a very rough approximation of [[E (mathematical constant)|''e'']], 2.71828...

3 is the first [[Mersenne prime]], as well as the second Mersenne prime exponent and the second [[Double Mersenne number#Double Mersenne primes|double Mersenne prime exponent]], for 7 and [[127 (number)|127]], respectively. 3 is also the first of five known [[Fermat prime]]s, which include 5, [[17 (number)|17]], [[257 (number)|257]], and [[65537 (number)|65537]]. It is the second [[Fibonacci number|Fibonacci prime]] (and the second [[Lucas prime]]), the second [[Sophie Germain prime]], the third Harshad number in base 10, and the second [[factorial prime]], as it is equal to 2! + 1. 

3 is the second and only prime [[triangular number]], and [[Gauss]] proved that every integer is the sum of at most 3 [[triangular numbers]].

Three is the only prime which is one less than a [[square number|perfect square]]. Any other number which is <math>n^2</math> − 1 for some integer <math>n</math> is not prime, since it is (<math>n</math> − 1)(<math>n</math> + 1). This is true for 3 as well (with <math>n</math> = 2), but in this case the smaller factor is 1. If <math>n</math> is greater than 2, both <math>n</math> − 1 and <math>n</math> + 1 are greater than 1 so their product is not prime.

=== Related properties ===
The [[trisection of the angle]] was one of the three famous problems of antiquity.

3 is the number of non-collinear points needed to determine a [[Plane (mathematics)|plane]], a [[circle]], and a [[parabola]].

There are only three distinct 4×4 [[panmagic square]]s.

Three of the five [[Platonic solids]] have triangular faces – the [[tetrahedron]], the [[octahedron]], and the [[icosahedron]]. Also, three of the five Platonic solids have [[vertex (geometry)|vertices]] where three faces meet&nbsp;– the [[tetrahedron]], the [[hexahedron]] ([[cube]]), and the [[dodecahedron]]. Furthermore, only three different types of [[polygons]] comprise the faces of the five Platonic solids&nbsp;– the [[triangle]], the [[square]], and the [[pentagon]].

There are three finite convex [[Uniform polyhedron|uniform polytope groups]] in three dimensions, aside from the infinite families of [[Prism (geometry)|prisms]] and [[antiprisms]]: the [[tetrahedral group]], the [[octahedral group]], and the [[icosahedral group]]. In dimensions <math>n</math> ⩾ 5, there are only three regular polytopes: the <math>n</math>-[[simplex]]es, <math>n</math>-[[cube]]s, and <math>n</math>-[[orthoplex]]es. In dimensions <math>n</math> ⩾ [[9]], the only three uniform polytope families, aside from the numerous infinite [[proprism]]atic families, are the <math>\mathrm{A}_{n}</math> simplex, <math>\mathrm{B}_{n}</math> cubic, and <math>\mathrm{D}_{n}</math> [[Demihypercube|demihypercubic]] families. For [[Coxeter–Dynkin diagram#Paracompact (Koszul simplex groups)|paracompact hyperbolic honeycomb]]s, there are three groups in [[dimension]]s [[Uniform 7-polytope#Regular and uniform hyperbolic honeycombs|6]] and [[Uniform 10-polytope#Regular and uniform hyperbolic honeycombs|9]], or equivalently of ranks 7 and 10, with no other forms in higher dimensions. Of the final three groups, the largest and most important is [[E9 honeycomb|<math>{\bar{T}}_9</math>]], that is associated with an important [[En (Lie algebra)|Kac–Moody]] [[Lie algebra]] <math>\mathrm {E}_{10}</math>.<ref>{{Cite journal |last1=Allcock |first1=Daniel |date=May 2018 |title=Prenilpotent Pairs in the E10 root lattice. |url=https://web.ma.utexas.edu/users/allcock/research/prenilpotent.pdf |url-status=live |journal=Mathematical Proceedings of the Cambridge Philosophical Society |volume=164 |issue=3 |pages=473–483 |bibcode=2018MPCPS.164..473A |doi=10.1017/S0305004117000287 |s2cid=8547735 |archive-url=https://web.archive.org/web/20221103135851/https://web.ma.utexas.edu/users/allcock/research/prenilpotent.pdf |archive-date=2022-11-03 |access-date=2022-11-03}} 

: "The details of the previous section were E10-specific, but the same philosophy looks likely to apply to the other symmetrizable hyperbolic root systems...it seems valuable to give an outline of how the calculations would go", regarding E10 as a model example of symmetrizability of other root hyperbolic E<sub>n</sub> systems.</ref>

=== Numeral systems ===
There is some evidence to suggest that early man may have used counting systems which consisted of "One, Two, Three" and thereafter "Many" to describe counting limits. Early peoples had a word to describe the quantities of one, two, and three but any quantity beyond was simply denoted as "Many". This is most likely based on the prevalence of this phenomenon among people in such disparate regions as the deep Amazon and Borneo jungles, where western civilization's explorers have historical records of their first encounters with these indigenous people.<ref>{{cite book | last1 = Gribbin | first1 = Mary  | last2 = Gribbin | first2 = John R. | last3 = Edney | first3 = Ralph | last4 = Halliday | first4 = Nicholas | title = Big numbers | publisher = Wizard | location = Cambridge | year = 2003 | isbn = 1840464313 }}</ref>

=== List of basic calculations ===
{|class="wikitable" style="text-align: center; background: white"
|-
!width="105px"|[[Multiplication]]
!1
!2
!3
!4
!5
!6
!7
!8
!9
!10
!11
!12
!13
!14
!15
!16
!17
!18
!19
!20
!21
!22
!23
!24
!25
!50
!100
!1000
!10000
|-
|'''3 × ''x'''''
|'''3'''
|[[6 (number)|6]]
|[[9 (number)|9]]
|[[12 (number)|12]]
|[[15 (number)|15]]
|[[18 (number)|18]]
|[[21 (number)|21]]
|[[24 (number)|24]]
|[[27 (number)|27]]
|[[30 (number)|30]]
|[[33 (number)|33]]
|[[36 (number)|36]]
|[[39 (number)|39]]
|[[42 (number)|42]]
|[[45 (number)|45]]
|[[48 (number)|48]]
|[[51 (number)|51]]
|[[54 (number)|54]]
|[[57 (number)|57]]
|[[60 (number)|60]]
|[[63 (number)|63]]
|[[66 (number)|66]]
|[[69 (number)|69]]
|[[72 (number)|72]]
|[[75 (number)|75]]
|[[150 (number)|150]]
|[[300 (number)|300]]
|[[3000 (number)|3000]]
|[[30000 (number)|30000]]
|}

{|class="wikitable" style="text-align: center; background: white"
|-
!width="105px"|[[Division (mathematics)|Division]]
!1
!2
!3
!4
!5
!6
!7
!8
!9
!10
!width="5px"|
!11
!12
!13
!14
!15
!16
!17
!18
!19
!20
|-
|'''3 ÷ ''x'''''
|'''3'''
|1.5
|1
|0.75
|0.6
|0.5
|0.{{overline|428571}}
|0.375
|0.{{overline|3}}
|0.3
!
|0.{{overline|27}}
|0.25
|0.{{overline|230769}}
|0.2{{overline|142857}}
|0.2
|0.1875
|0.1{{overline|7647058823529411}}
|0.1{{overline|6}}
|0.1{{overline|57894736842105263}}
|0.15
|-
|'''''x'' ÷ 3'''
|0.{{overline|3}}
|0.{{overline|6}}
|1
|1.{{overline|3}}
|1.{{overline|6}}
|2
|2.{{overline|3}}
|2.{{overline|6}}
|'''3'''
|3.{{overline|3}}
!
|3.{{overline|6}}
|4
|4.{{overline|3}}
|4.{{overline|6}}
|5
|5.{{overline|3}}
|5.{{overline|6}}
|6
|6.{{overline|3}}
|6.{{overline|6}}
|}

{|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
!13
!14
!15
!16
!17
!18
!19
!20
|-
|'''3{{sup|''x''}}'''
|'''3'''
|9
|27
|[[81 (number)|81]]
|[[243 (number)|243]]
|729
|2187
|6561
|19683
|59049
!
|177147
|531441
|1594323
|4782969
|14348907
|43046721
|129140163
|387420489
|1162261467
|3486784401
|-
|'''''x''{{sup|3}}'''
|1
|[[8 (number)|8]]
|27
|[[64 (number)|64]]
|[[125 (number)|125]]
|[[216 (number)|216]]
|[[343 (number)|343]]
|[[512 (number)|512]]
|729
|[[1000 (number)|1000]]
!
|1331
|1728
|2197
|2744
|3375
|4096
|4913
|5832
|6859
|8000
|}

==Science==
*Three is the [[atomic number]] of [[lithium]].
*Three is the number of [[Dimension (mathematics and physics)|dimensions]] that humans can perceive. Humans perceive the [[universe]] to have [[Three-dimensional space|three spatial dimensions]], but some theories, such as [[string theory]], suggest there are more.<ref>{{Cite book |last=Zwiebach |first=Barton |title=A first course in string theory |date=2009 |publisher=Cambridge University Press |isbn=978-0-521-88032-9 |edition=2nd |location=Cambridge ; New York}}</ref>
*Three is the number of elementary fermion [[Generation (particle physics)|generations]] according to the [[Standard Model]] of particle physics.<ref>
{{cite conference
 |last = Harari |first = H.
 |year = 1977
 |title = Three generations of quarks and leptons
 |book-title = Proceedings of the XII Rencontre de Moriond
 |editor1 = van Goeler, E.
 |editor2 = Weinstein, R.
 |page = 170
 |id = SLAC-PUB-1974
 |url = http://slac.stanford.edu/cgi-wrap/getdoc/slac-pub-1974.pdf
}}
</ref>
*In [[particle physics]], each [[proton]] or [[neutron]] is composed of three [[quarks]].<ref>
{{cite book
|author=Adair, R.K.
|year=1989
|title=The Great Design: Particles, Fields, and Creation
|page=214
|publisher=[[Oxford University Press]]
|bibcode=1988gdpf.book.....A
}}</ref>
*There are three [[primary color]]s in the [[additive color|additive]] and [[subtractive color|subtractive]] models.
*The ability of the [[human eye]] to distinguish [[color]]s is based upon the varying sensitivity of different cells in the [[retina]] to light of different [[wavelengths]]. Humans being [[Trichromacy|trichromatic]], the retina contains three types of color receptor cells, or [[cone cell|cones]].<ref>{{Cite web |title=The Rods and Cones of the Human Eye |url=http://hyperphysics.phy-astr.gsu.edu/hbase/vision/rodcone.html |access-date=2024-06-04 |website=hyperphysics.phy-astr.gsu.edu}}</ref>
*In [[physics]], [[three-body problem|three-body problems]] have no general [[closed-form solution]], unlike [[two-body problem|two-body problems]].<ref>{{cite encyclopedia
| last  = Barrow-Green
| first = June
| year  = 2008
| title = The Three-Body Problem
| editor-last1  = Gowers
| editor-first1 = Timothy
| editor-last2  = Barrow-Green
| editor-first2 = June
| editor-last3 = Leader
| editor-first3 = Imre
| encyclopedia = The Princeton Companion to Mathematics
| pages  = 726–728
| publisher = Princeton University Press
}}</ref>

==Engineering==
*The [[triangle]], a [[polygon]] with three [[Edge (geometry)|edges]] and three [[Vertex (geometry)|vertices]], is the most stable physical shape. For this reason it is widely utilized in construction, engineering and design.<ref>"[https://web.archive.org/web/20120412203618/http://www.mathsinthecity.com/sites/most-stable-shape-triangle Most stable shape- triangle]". ''Maths in the city''. Retrieved February 23, 2015.</ref>

===Protoscience===
*In European [[alchemy]], the three primes ({{langx|la|tria prima}}) were [[salt (chemistry)|salt]] ([[File:Salt symbol (alchemical).svg|16px]]), [[sulfur]] ([[Image:Sulphur symbol (fixed width).svg|16px]]) and [[mercury (element)|mercury]] ([[Image:Mercury symbol (fixed width).svg|16px]]).<ref name="Eric John Holmyard 1990. p.153">Eric John Holmyard. ''Alchemy.'' 1995. p.153</ref><ref>Walter J. Friedlander. ''The golden wand of medicine: a history of the caduceus symbol in medicine.'' 1992. p.76-77</ref>
*The three [[doshas]] (weaknesses) and their [[antidote]]s are the basis of [[Ayurvedic medicine]] in India.<ref>{{Cite web |last=Kreidler |first=Marc |date=2017-12-14 |title=Ayurveda: Ancient Superstition, Not Ancient Wisdom |url=https://skepticalinquirer.org/exclusive/ayurveda-ancient-superstition-not-ancient-wisdom/ |access-date=2024-06-04 |website=Skeptical Inquirer |language=en-US}}</ref>

===Pseudoscience===
*Three is the symbolic representation for [[Mu (lost continent)|Mu]], [[Augustus Le Plongeon]]'s and [[James Churchward]]'s lost continent.<ref name="Three is for the Lost Continent of Mu">{{cite web |url=http://www.bibliotecapleyades.net/atlantida_mu/contmu/contmu09.htm |title=The Lost Continent of Mu – Symbols, Vignettes, Tableaux and Diagrams |first=James |last=Churchward |year=1931 |access-date=2016-03-15 |work=Biblioteca Pleyades |archive-date=2015-07-18 |archive-url=https://web.archive.org/web/20150718115213/http://www.bibliotecapleyades.net/atlantida_mu/contmu/contmu09.htm |url-status=live }}</ref>

==Philosophy==
{{Main article|Trichotomy (philosophy)}}
*Philosophers such as [[Aquinas]], [[Immanuel Kant|Kant]], [[Hegel]], [[Charles Sanders Peirce|C.&nbsp;S. Peirce]], and [[Karl Popper]] have made threefold divisions, or ''[[Trichotomy (philosophy)|trichotomies]]'', which have been important in their work.{{citation needed|date=October 2023}}
*[[Hegel]]'s [[Dialectic#Hegelian dialectic|dialectic]] of [[Thesis, antithesis, synthesis|Thesis + Antithesis = Synthesis]] creates three-ness from two-ness.{{citation needed|date=October 2023}}
* In a 1931 interview, [[Nikola Tesla]] allegedly said, "If you only knew the magnificence of the 3, 6, and 9, then you would have a key to the universe." {{citation needed|date=July 2024}}

==Religion==
{{prose|section|date=October 2023}}{{more references|section|date=October 2023}}
{{See also|Triple deity}}
[[File:Triple Goddess Symbol.svg|thumb|right|Symbol of the Triple Goddess showing the waxing, full and waning Moon]]

Many world religions contain triple deities or concepts of trinity, including the [[Hindu]] [[Trimurti]] and [[Tridevi]], the [[Triglav (mythology)|Triglav]] (lit. "Three-headed one"), the chief god of the [[slav]]s, the [[three Jewels]] of [[Buddhism]], the [[three Pure Ones]] of [[Taoism]], the [[Christianity|Christian]] [[Trinity|Holy Trinity]], and the [[Triple Goddess (Neopaganism)|Triple Goddess]] of [[Wicca]].

[[File:Shield-Trinity-Scutum-Fidei-English.svg|thumb|The [[Shield of the Trinity]] is a diagram of the Christian doctrine of the Trinity.]]

===Christianity===
*The [[threefold office]] of [[Christ]] is a Christian doctrine which states that Christ performs the functions of [[prophet]], [[priest]], and [[Christ the king|king]].
*During the [[Agony in the Garden]], Christ asked three times for the cup to be taken from him.
*Jesus [[Resurrection of Jesus|rose from the dead]] on the third day after his death.
*The [[Temptation of Christ|devil tempted Jesus]] three times.
*[[Saint Peter]] [[Denial of Peter|thrice denied Jesus]] and [[Restoration of Peter|thrice affirmed his faith in Jesus]].
*The [[Biblical magi|Magi]] – wise men who were astronomers/astrologers from Persia<ref>{{Cite web |last=Windle |first=Bryan |date=2022-12-22 |title=Who Were the Magi? |url=https://biblearchaeologyreport.com/2022/12/22/who-were-the-magi/ |access-date=2024-07-05 |website=Bible Archaeology Report |language=en}}</ref> – gave Jesus three gifts.<ref>{{Cite journal |title=Encyclopaedia Britannica |doi=10.1163/9789004337862_lgbo_com_050367 |journal=Lexikon des Gesamten Buchwesens Online |language=de}}</ref><ref>{{Cite journal |title=The Encyclopaedia Britannica |journal=Nature |url=https://zenodo.org/record/1609149 |date=25 January 1877 |volume=XV |issue=378 |pages=269–271 |access-date=12 July 2019 |archive-date=24 July 2020 |archive-url=https://web.archive.org/web/20200724194916/https://zenodo.org/record/1609149 |url-status=live }}</ref>
*There are three [[Synoptic Gospels]] and three [[epistles of John]].
*[[Paul the Apostle]] went blind for three days after his [[Conversion of Paul the Apostle|conversion to Christianity]].

===Judaism===
*[[Noah]] had three sons: [[Ham (son of Noah)|Ham]], [[Shem]] and [[Japheth]]
*The Three [[Patriarchs (Bible)|Patriarchs]]: [[Abraham]], [[Isaac]] and [[Jacob]]
*The prophet [[Balaam]] beat his donkey three times.
*The prophet [[Jonah]] spent three days and nights in the belly of a large fish
*Three divisions of the Written [[Torah]]: [[Torah]] (Five Books of Moses), [[Nevi'im]] (Prophets), [[Ketuvim]] (Writings)<ref name=why>{{cite web |url=http://www.askmoses.com/en/article/228,503/Why-are-many-things-in-Judaism-done-three-times.html |title=Why are many things in Judaism done three times? |first=Rabbi Yossi |last=Marcus |year=2015 |access-date=16 March 2015 |work=Ask Moses |archive-date=2 April 2015 |archive-url=https://web.archive.org/web/20150402134737/http://www.askmoses.com/en/article/228,503/Why-are-many-things-in-Judaism-done-three-times.html |url-status=dead }}</ref>
*Three divisions of the Jewish people: [[Kohen]], [[Levite]], Yisrael
*Three daily [[Jewish prayer|prayers]]: ''[[Shacharit]]'', ''[[Mincha]]'', ''[[Maariv]]''
*Three [[Shabbat]] meals
*Shabbat ends when three stars are visible in the night sky<ref>{{cite web |url=http://www.jewfaq.org/shabbat.htm |title=Shabbat |work=Judaism 101 |year=2011 |access-date=16 March 2015 |archive-date=29 June 2009 |archive-url=https://web.archive.org/web/20090629025034/http://www.jewfaq.org/shabbat.htm |url-status=live }}</ref>
*[[Three Pilgrimage Festivals]]: [[Passover]], [[Shavuot]], [[Sukkot]]
*Three [[Matzah|matzo]]s on the [[Passover Seder]] table<ref>{{cite web |url=http://www.chabad.org/holidays/passover/pesach_cdo/aid/1702/jewish/The-Three-Matzot.htm |title=The Three Matzot |first=Eliyahu |last=Kitov |author-link=Eliyahu Kitov |year=2015 |work=Chabad.org |access-date=16 March 2015 |archive-date=24 March 2015 |archive-url=https://web.archive.org/web/20150324124011/http://www.chabad.org/holidays/passover/pesach_cdo/aid/1702/jewish/The-Three-Matzot.htm |url-status=live }}</ref>
*[[The Three Weeks]], a period of mourning bridging the fast days of [[Seventeenth of Tammuz]] and [[Tisha B'Av]]
*Three cardinal sins for which a Jew must die rather than transgress: [[Idolatry#Judaism|idolatry]], [[murder]], [[Immorality#Sexual immorality|sexual immorality]]<ref>{{cite web |url=http://www.aish.com/jl/m/pm/48936542.html |title=Judaism and Martyrdom |first=Rabbi Aryeh |last=Kaplan |author-link=Aryeh Kaplan |date=28 August 2004 |access-date=16 March 2015 |publisher=Aish.com |archive-date=20 March 2015 |archive-url=https://web.archive.org/web/20150320081912/http://www.aish.com/jl/m/pm/48936542.html |url-status=live }}</ref>
*[[Upsherin]], a Jewish boy's first haircut at age 3<ref>{{cite web |url=http://www.chabad.org/library/article_cdo/aid/710724/jewish/The-Basics-of-the-Upsherin.htm |title=The Basics of the Upsherin: A Boy's First Haircut |year=2015 |access-date=16 March 2015 |work=Chabad.org |archive-date=22 March 2015 |archive-url=https://web.archive.org/web/20150322124639/http://www.chabad.org/library/article_cdo/aid/710724/jewish/The-Basics-of-the-Upsherin.htm |url-status=live }}</ref>
*A [[Beth din]] is composed of three members
*Potential [[Conversion to Judaism|converts]] are traditionally turned away three times to test their sincerity<ref>{{cite web |url=http://www.convert.org/Conversion_Process.html |title=The Conversion Process |publisher=Center for Conversion to Judaism |access-date=16 March 2015 |archive-date=23 February 2021 |archive-url=https://web.archive.org/web/20210223162821/http://www.convert.org/Conversion_Process.html |url-status=live }}</ref>
*In the [[Jewish mysticism|Jewish mystical]] tradition of the [[Kabbalah]], it is believed that [[the soul]] consists of three parts, with the highest being ''[[Soul#Judaism|neshamah]]'' ("breath"), the middle being ''[[ruach]]'' ("wind" or "spirit") and the lowest being ''[[Nephesh|nefesh]]'' ("repose").<ref>Kaplan, Aryeh. "[http://www.aish.com/jl/sp/bas/48942091.html The Soul] {{Webarchive|url=https://web.archive.org/web/20150224124738/http://www.aish.com/jl/sp/bas/48942091.html |date=2015-02-24 }}". ''Aish''. From ''The Handbook of Jewish Thought'' (Vol. 2, ''Maznaim Publishing''. Reprinted with permission.) September 4, 2004. Retrieved February 24, 2015.</ref> Sometimes the two elements of ''Chayah'' ("life" or "animal") and ''Yechidah'' ("unit") are additionally mentioned.
*In the Kabbalah, the [[Tree of life (Kabbalah)|Tree of Life]] (Hebrew: ''Etz ha-Chayim'', עץ החיים) refers to a latter 3-pillar diagrammatic representation of its central mystical symbol, known as the ''[[Sephirot|10 Sephirot]]''.

===Islam===
*The three core principles in Shia tradition: Tawhid (Oneness of God), Nabuwwa (Concept of Prophethood), Imama (Concept of Imam)

===Buddhism===
*The Triple [[Bodhi]] (ways to understand the end of birth) are Budhu, Pasebudhu, and Mahaarahath.
*The [[Three Jewels]], the three things that Buddhists take refuge in.

===Shinto===
*The [[Imperial Regalia of Japan]] of the sword, mirror, and jewel.

===Daoism===
*The [[Three Treasures (Taoism)|Three Treasures]] ({{zh|c=[[Wikt:三|三]][[Wikt:寶|寶]]|p=''sānbǎo''| w=''san-pao''}}), the basic [[virtues]] in [[Taoism]].
*The Three [[Dantian]]s
*Three Lines of a [[Bagua|Trigram]]
*[[Three Sovereigns]]: Heaven [[Fu Xi]] (Hand – Head – 3º Eye), Humanity [[Shen Nong]] ([[Liang Yi|Unit 69]]), Hell [[Nüwa]] (Foot – Abdomen – Umbiculus).

===Hinduism===
*The [[Trimurti]]: [[Brahma]] the Creator, [[Vishnu]] the Preserver, and [[Shiva]] the Destroyer.
*The three [[guṇa]]s (''triguna'') found in the [[Samkhya]] school of Hindu philosophy.<ref>James G. Lochtefeld, Guna, in The Illustrated Encyclopedia of Hinduism: A-M, Vol. 1, Rosen Publishing, {{ISBN|978-0-8239-3179-8}}, page 265</ref>
*The three paths to salvation in the ''[[Bhagavad Gita]]'' named [[Karma Yoga]], [[Bhakti Yoga]] and [[Jnana Yoga]].

===Zoroastrianism===
*The three virtues of ''Humata'', ''Hukhta'' and ''Huvarshta'' (Good Thoughts, Good Words and Good Deeds) are a basic tenet in [[Zoroastrianism]].

===Norse mythology===
Three is a very significant number in [[Norse mythology]], along with its powers 9 and 27.
*Prior to [[Ragnarök]], there will be three hard winters without an intervening summer, the [[Fimbulwinter]].
*Odin endured three hardships upon the World Tree in his quest for the [[runic alphabet|runes]]: he hanged himself, wounded himself with a spear, and suffered from hunger and thirst.
*[[Borr|Bor]] had three sons, [[Odin]], [[Vili]], and [[Vé]].

===Other religions===
*The [[Wicca]]n [[Rule of Three (Wiccan)|Rule of Three]].
*The [[Triple Goddess (Neopaganism)|Triple Goddess]]: Maiden, Mother, Crone; the three fates.
*The sons of [[Cronus]]: [[Zeus]], [[Poseidon]], and [[Hades]].
*The Slavic god [[Triglav (mythology)|Triglav]] has three heads.

===Esoteric tradition===
*The [[Theosophical Society]] has [[Theosophy (Blavatskian)|three conditions of membership]].
*[[Gurdjieff]]'s [[Three Centres|Three Centers]] and the [[Fourth Way|Law of Three]].
*''[[Liber AL vel Legis]]'', the central scripture of the religion of [[Thelema]], consists of three chapters, corresponding to three divine narrators respectively: [[Nuit]], [[Hadit]] and [[Ra-Hoor-Khuit]].
*The Triple Greatness of [[Hermes Trismegistus]] is an important theme in [[Hermeticism]].

===As a lucky or unlucky number===
{{refimprove section|date=April 2009}}
Three ({{lang|zh|三}}, formal writing: {{lang|zh|叁}}, [[pinyin]] ''sān'', [[Cantonese]]: ''saam''<sup>1</sup>) is considered a [[numerology|good number]] in [[Chinese culture]] because it sounds like the word "alive" ({{lang|zh|生}} pinyin ''shēng'', Cantonese: ''saang''<sup>1</sup>), compared to [[4 (number)|four]] ({{lang|zh|四}}, pinyin: ''sì'', Cantonese: ''sei''<sup>1</sup>), which sounds like the word "death" ({{lang|zh|死}} pinyin ''sǐ'', Cantonese: ''sei''<sup>2</sup>).

Counting to three is common in situations where a group of people wish to perform an action in [[Synchronization|synchrony]]: ''Now, on the count of three, everybody pull!'' Assuming the counter is proceeding at a uniform rate, the first two counts are necessary to establish the rate, and the count of "three" is predicted based on the timing of the "one" and "two" before it. Three is likely used instead of some other number because it requires the minimal amount counts while setting a rate.

There is another superstition that it is unlucky to take a [[Three on a match (superstition)|third light]], that is, to be the third person to light a cigarette from the same match or lighter. This superstition is sometimes asserted to have originated among soldiers in the trenches of the First World War when a sniper might see the first light, take aim on the second and fire on the third.{{citation needed|date=May 2021}}

The phrase "[[:wikt:Third time's the charm|Third time's the charm]]" refers to the superstition that after two failures in any endeavor, a third attempt is more likely to succeed. This is also sometimes seen in reverse, as in "third man [to do something, presumably forbidden] gets caught". {{citation needed|date=May 2021}}

[[Luck]], especially bad luck, is often said to "come in threes".<ref>See "[http://www.encyclopedia.com/doc/1O214-bad.html bad] {{Webarchive|url=https://web.archive.org/web/20090302124523/http://www.encyclopedia.com/doc/1O214-bad.html |date=2009-03-02 }}" in the ''Oxford Dictionary of Phrase and Fable'', 2006, via Encyclopedia.com.</ref>

==See also==
{{Portal|Mathematics}}
*[[Cube (algebra)]] – (3 [[superscript]])
*[[Thrice]]
*[[Third (disambiguation)|Third]]
*[[Triad (disambiguation)|Triad]]
*[[Trio (disambiguation)|Trio]]
*[[Rule of three (disambiguation)|Rule of three]]
* [[Open-mid central unrounded vowel|ɜ]], {{unichar|025C}} also known as [[Open-mid central unrounded vowel|Reversed epsilon]]
*[[List of highways numbered 3]]

==References==
{{Reflist|30em}}

=== Bibliography ===
*Wells, D. ''[[The Penguin Dictionary of Curious and Interesting Numbers]]'' London: Penguin Group. (1987): 46&ndash;48

==External links==
{{Wiktionary|three}}
{{Commons category}}
*[https://web.archive.org/web/20071023064015/http://threes.com/ Tricyclopedic Book of Threes] by Michael Eck
*[http://www.meddean.luc.edu/lumen/MedEd/GrossAnatomy/Threes.html Threes in Human Anatomy] by John A. McNulty
*{{cite web|last=Grime|first=James|title=3 is everywhere|url=http://www.numberphile.com/videos/three.html|work=Numberphile|publisher=[[Brady Haran]]|access-date=2013-04-13|archive-url=https://web.archive.org/web/20130514230849/http://www.numberphile.com/videos/three.html|archive-date=2013-05-14|url-status=dead}}
*[https://web.archive.org/web/20140201161634/http://numdic.com/3 The Number 3]
*[http://www.positiveintegers.org/3 The Positive Integer 3]
*[http://primes.utm.edu/curios/page.php/3.html Prime curiosities: 3]

{{Integers|zero}}
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{{DEFAULTSORT:3 (Number)}}
[[Category:Integers]]
[[Category:3 (number)| ]]