Omega: Difference between revisions

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Latest revision as of 04:56, 11 August 2025

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{{TableShort Greeklettersdescription|Last letter=omega of the Greek alphabet}}

{{Redirect|Ω|the unit of electrical resistance|Ohm}}

{{SpecialCharsNote}}

{{about|the Greek letter|the Cyrillic letter|Omega (Cyrillic)|the Latin letter |Latin omega}}

{{otheruses}}

{{Other uses}}

{{More citations needed|date=December 2014}}

{{Use dmy dates|date=April 2023}}

{{Greek Alphabet|letter=omega}}'''Omega''' ({{IPAc-en|US|oʊ|ˈ|m|eɪ|ɡ|ə|,_|-|ˈ|m|ɛ|ɡ|ə|,_|-|ˈ|m|iː|ɡ|ə|audio=LL-Q1860 (eng)-Flame, not lame-Omega.wav}}, {{IPAc-en|UK|ˈ|oʊ|m|ɪ|ɡ|ə|}};<ref>{{cite LPD|3|omega}}</ref> <!-- <ref>{{OED|omega}}</ref><ref>{{cite Dictionary.com|omega}}</ref> -->uppercase '''Ω''', lowercase '''ω''') is the twenty-fourth and last letter in the [[Greek alphabet]]. In the [[Greek numerals|Greek numeric system]]/[[isopsephy]] ([[gematria]]), it has a value of 800. The name of the letter was originally {{lang|grc|ὦ}} ({{transliteration|grc|ō̂}} {{IPA|grc|ɔ̂ː|}}), but it was later changed to {{wikt-lang|grc|ὦ μέγα}} ({{transliteration|grc|ō̂ méga}} 'big o') in the Middle Ages to distinguish it from [[omicron]] {{angbr|{{lang|grc|ο}}}}, whose name means 'small o', as both letters had come to be pronounced {{IPA|grc-x-medieval|o|}}.<ref>{{cite web |url=http://www.quinapalus.com/gr0.1.html |title=The Greek Alphabet }}</ref> In [[modern Greek]], its name has fused into {{lang|el|ωμέγα}} ({{transliteration|el|oméga}}).

In [[Phonetics|phonetic]] terms, the Ancient Greek Ω represented a [[vowel length|long]] [[open-mid back rounded vowel]] {{IPA|grc|ɔː|}}, in contrast to [[omicron]], which represented the [[close-mid back rounded vowel]] {{IPA|grc|o|}}, and the [[digraph (orthography)|digraph]] {{angbr|{{lang|grc|ου}}}}, which represented the [[vowel length|long]] [[close back rounded vowel]] {{IPA|grc|uː|}}. In [[modern Greek]], both omega and omicron represent the [[mid back rounded vowel]]<!-- not close-mid, see Arvanti (1999) - Illustrations of the IPA: Modern Greek. --> {{IPA|el|o̞|}}. The letter omega is [[transliteration|transliterated]] into a [[Latin-script alphabet]] as {{transliteration|el|ō}} or simply {{transliteration|el|o}}.

'''Omega''' (Ω ω) is the 24th and last letter of the [[Greek alphabet]]. In the [[Greek numerals|Greek numeric system]] it had a value of 800. The word literally means "big&nbsp;O" (''ō [[mega]]'', mega meaning 'big'), as opposed to [[Omicron]], which means "little&nbsp;O" (''o [[metre|mikron]]'', micron meaning 'little').[http://www.quinapalus.com/gr0.1.html] This name is [[Medieval Greek|Byzantine]]; in [[Ancient Greek|Classical Greek]], the letter was called ''ō'' ({{Polytonic|ὦ}}), whereas the [[Omicron]] was called ''ou'' ({{Polytonic|οὖ}}).

As the final letter in the Greek alphabet, omega is often used to denote the last, the end, or the ultimate limit of a [[set theory|set]], in contrast to [[Alpha (letter)|alpha]], the first letter of the Greek alphabet; see [[Alpha and Omega]].

Phonetically, the [[Ancient Greek]] Ω is a long ''o'', similar to the vowel of English ''close''. It is [[Transcription (linguistics)|transcribed]] ''ō'' or simply ''o''. In [[Modern Greek]] Ω is a short ''o'' similar to the vowel of English ''pot''.

==History==

Omega is often used to denote the last, the end, or the ultimate limit of a [[set theory|set]], in contrast to [[Alpha (letter)|Alpha]], the first letter of the Greek Alphabet. [[Jesus]] declares himself to be the "Alpha and Omega, the beginning and the end, the first and the last", ([[Book of Revelation|Revelation]] 22:13, KJV, and see also 1:8), Greek {{Polytonic|ἐγὼ τὸ ἄλφα καὶ τὸ ὦ, ὁ πρῶτος καὶ ὁ ἔσχατος, ἡ ἀρχὴ καὶ τὸ τέλος}}.

Ω was not part of the early (8th century BC) [[Archaic Greek alphabets|Greek alphabets]]. It was introduced in the late 7th century BC in the Ionian cities of Asia Minor to denote a [[vowel length|long]] [[open-mid back rounded vowel]] {{IPA|[ɔː]}}. It is a variant of omicron (Ο), broken up at the side ([[File:Greek Omega 09.svg|x16px]]), with the edges subsequently turned outward ({{GrGl|Omega 09}}, {{GrGl|Omega 05}}, {{GrGl|Omega 03}}, {{GrGl|Omega 07}}).<ref name="Jeffery37f">Anne Jeffery (1961), ''The Local Scripts of Archaic Greece'', pp. 37–38.</ref> The Dorian city of [[Knidos]] as well as a few Aegean islands, namely [[Paros]], [[Thasos]] and [[Melos]], chose the exact opposite innovation, using a broken-up circle for the short and a closed circle for the long {{IPA|/o/}}.<ref name=Jeffery37f/>

The name Ωμέγα is [[Medieval Greek|Byzantine]]; in [[Ancient Greek|Classical Greek]], the letter was called ''ō'' ({{lang|grc|ὦ}}) (pronounced /ɔ̂ː/), whereas the omicron was called ''ou'' ({{lang|grc|οὖ}}) (pronounced /ôː/).<ref>Herbert Weir Smyth ''A Greek Grammar for Colleges'' §1.</ref> The modern lowercase shape goes back to the [[uncial]] form [[File:Greek uncial Omega.svg|x14px]], a form that developed during the 3rd century BC in ancient handwriting on papyrus, from a flattened-out form of the letter ([[File:Greek Omega 08.svg|x16px]]) that had its edges curved even further upward.<ref>Edward M. Thompson (1912), ''Introduction to Greek and Latin Paleography'', Oxford: Clarendon, p. 144.</ref>

Omega was also adopted into the [[early Cyrillic alphabet]]. See [[omega (Cyrillic)]] (Ѡ, ѡ).

In addition to the Greek alphabet, Omega was also adopted into the [[early Cyrillic alphabet]] (see [[omega (Cyrillic)|Cyrillic omega]] (Ѡ, ѡ)). A [[Raetic alphabet|Raetic]] variant is conjectured to be at the origin or parallel evolution of the [[Elder Futhark]] [[ᛟ]].

== The symbol Ω (upper-case letter) ==

The upper-case letter Ω is used as a symbol.

=== In Reality ===

*For [[Ohm (unit)|ohm]] — [[SI]] unit of electrical resistance; formerly also used upside down (℧) to represent [[mho]], the old name for the inverse of an ohm (now [[siemens (unit)|siemens]] with symbol S) used for electrical conductance. [[Unicode]] has a separate code point for the [[Ohm (unit)|ohm]] sign (U+2126), but it is only included for backwards compatibility and the Greek uppercase omega character (U+03A9, Ω) is preferred.

*In the late 1960s [[United States]], it was used as an icon/symbol for [[Conscription#Draft_resisters|draft resistance]].

*In [[computer science]], in notation related to [[Big O notation]] to describe the [[asymptotic behavior]] of [[function (mathematics)|function]]s. See also [[Chaitin's constant]]

*''Codex Athous Dionysii'', an 8th/9th century [[uncial]] [[Greek language|Greek]] manuscript of the [[Gospel]]s on [[Mount Athos]]

*[[Omega Point]], a theory about computing at the end of the universe

*In [[mathematics]], the [[Omega constant]], a solution of [[Lambert's W function]]; or the first [[uncountable set|uncountable]] [[ordinal number]] (also known as <math>\omega_1</math>)

*In [[physics]], the [[solid angle]].

*In [[particle physics]] to represent the [[Omega baryon]]s. A lowercase omega is used for the [[omega meson]]s.

*In [[combinatory logic]], the looping combinator, ''(λ x. x x)(λ x. x x)''

*For the [[Lebanon|Lebanese]] political party: the [[Free Patriotic Movement]]

*A Prestige Swiss watch company named [[Omega Watches|Omega]] [[http://www.omega.ch]]

*The logo of [[Lululemon Athletica]] is often mistaken for a stylized Ω, but the company claims it is in fact a stylized [[A]].

*Since Omega is the last letter of the Greek alphabet, it sometimes represents the end. The saying "alpha and the omega" means "the beginning and the end," and is also a [[Christian]] reference to [[Jesus]]. References in popular culture include a movie titled "[[The Omega Man]]", whose main character became the last living human. One of Agent Smith's lines from the Matrix Reloaded echoes the biblical phrase as well, with Smith calling himself the [[Alpha]] of Neo's Omega, or the beginning of his end.

*In [[astronomy]] ([[cosmology]]) Ω refers to the density of the universe, also called the [[Friedmann_equations#The_density_parameter|density parameter]].

=== In Pop Culture and Fiction ===

* [[Naoki Maeda]]'s [[pseudonym]] for the ''[[Dance Dance Revolution]]'' song "MAX 300"

* The symbol was on Cassandra's shield in [[Soul Calibur 2]]

* In [[Mega Man Zero]] games, the [[utopia]] Neo Arcadia bears the Ω symbol during the course of the game. Ω is also used as a boss' allegiance symbol until Mega Man Zero 3.

* In the [[PlayStation 2|PS2]] game [[God of War]] Ω is used in many different areas including the title where the symbol surounds "Of".

* On the NBC soap opera [[Passions]] the omega symbol is being featured frequently as part of the Passions Vendetta storyline.

Omega was also adopted into the Latin alphabet, as a letter of the 1982 revision to the [[African reference alphabet]]. It's in sparse use (see [[Latin omega]]).

== The symbol ω (lower-case letter) ==

The lower-case letter ω is used as a symbol:

*In [[textual criticism]], the [[archetype]] of a manuscript tradition

*In [[physics]], [[angular velocity]]

*In [[mathematics]], the first [[transfinite number|transfinite]] [[ordinal number]]

*In [[number theory]], an [[arithmetic function]]

*In [[combinatory logic]], the self-application combinator, ''(λ x. x x)''

*In [[computer science]], in notation related to [[Big O notation]], the [[asymptotically dominant]] nature of [[function (mathematics)|function]]s

*In [[Astronomy]], as a ranking of a star's brightness

*In [[particle physics]] to represent the [[Meson|omega meson]]

*In [[Circuit Analysis]] and [[Signal Processing]] to represent [[frequency]].

*In [[Biochemistry]] to denote the carbon atom furthest from the [[carboxyl group]] of a [[fatty acid]].

== The symbol Ω (uppercase letter) ==

[[Category:Greek letters]]

[[File:Kos città, piazza eleftherias, edificio razionalista, targa.JPG|thumb|Plaque in [[Kos]] with "underlined O" form of omega]]

The [[Upper case|uppercase]] letter Ω is used as a symbol:

[[als:Ω]]

* In [[chemistry]]:

[[bg:Омега]]

** For [[oxygen-18]], a natural, stable isotope of oxygen<ref name="geoENV2012">{{cite web |last1=Capilla |first1=José E. |last2=Arevalo |first2=Javier Rodriguez |last3=Castaño |first3=Silvino Castaño |last4=Teijeiro |first4=María Fé Díaz |last5=del Moral |first5=Rut Sanchez |last6=Diaz |first6=Javier Heredia |title=Mapping Oxygen-18 in Meteoric Precipitation over Peninsular Spain Using Geostatistical Tools |url=http://www.cedex.es/NR/rdonlyres/B8A9522A-5D6F-4675-921A-24BB8458187B/124720/Capilla_et_al_geoENV_2012_Valencia_Espa%C3%B1a_Extended.pdf |website=cedex.es |publisher=Ninth Conference on Geostatistics for Environmental Applications |___location=Valencia, Spain |date=19 September 2012 |access-date=8 May 2017 |archive-date=23 September 2015 |archive-url=https://web.archive.org/web/20150923201512/http://www.cedex.es/NR/rdonlyres/B8A9522A-5D6F-4675-921A-24BB8458187B/124720/Capilla_et_al_geoENV_2012_Valencia_Espa%C3%B1a_Extended.pdf |url-status=dead }}</ref>

[[ca:Omega]]

** For [[omega loop]], a protein structural motif consisting of a loop of six or more amino acid residues in any sequence, a structure named for its resemblance to the Greek letter.<ref>{{Cite journal |last=Krishna |first=Mallela M. G. |last2=Lin |first2=Yan |last3=Rumbley |first3=Jon N. |last4=Walter Englander |first4=S. |date=2003-08-01 |title=Cooperative Omega Loops in Cytochrome c: Role in Folding and Function |url=https://www.sciencedirect.com/science/article/abs/pii/S0022283603006971 |journal=Journal of Molecular Biology |volume=331 |issue=1 |pages=29–36 |doi=10.1016/S0022-2836(03)00697-1 |issn=0022-2836|url-access=subscription }}</ref>

[[da:Omega (bogstav)]]

* In [[de:Omegaphysics]]:

** For [[ohm]] – SI unit of electrical resistance.<ref>{{Cite web |date=2025-01-03 |title=Ohm {{!}} Electricity, Resistance & Voltage {{!}} Britannica |url=https://www.britannica.com/science/ohm |access-date=2025-02-08 |website=www.britannica.com |language=en}}</ref> Unicode has a separate code point {{unichar|2126|OHM SIGN}} ([[HTML entity]] <code>&amp;ohm;</code>), but it is included only for backward compatibility, and the canonically equivalent code point {{unichar|03A9|GREEK CAPITAL LETTER OMEGA}} (<code>&amp;Omega;</code>) is preferred. Also formerly also used upside down ({{unichar|2127|INVERTED OHM SIGN}}) to represent [[mho]], the old name for the inverse of an ohm (now siemens with symbol S), the SI unit of electrical conductance.<ref>Excerpts from ''[https://www.unicode.org/versions/Unicode4.0.0/ch07.pdf#search=%22character%20U%2B2126%20maps%20OR%20map%20OR%20mapping%22 The Unicode Standard, Version 4.0]''. Retrieved 11 October 2006.</ref>

[[el:Ωμέγα]]

** In [[statistical mechanics]], Ω refers to the multiplicity (number of microstates) in a system.

[[es:Ω]]

** The [[solid angle]]<ref>{{Cite web |last=Weisstein |first=Eric W. |title=Solid Angle |url=https://mathworld.wolfram.com/SolidAngle.html |access-date=2025-02-07 |website=mathworld.wolfram.com |language=en |quote=The solid angle Ω subtended by a surface S is defined as the surface area Ω of a unit sphere covered by the surface's projection onto the sphere.}}</ref> or the rate of precession in a gyroscope

[[eo:OMEGA]]

** In particle physics to represent the [[Omega baryon]]s

[[fr:Oméga]]

** In astronomy (cosmology), Ω refers to the average density of the universe, also called the [[density parameter]].

[[gl:Omega]]

** In astronomy (orbital mechanics), Ω refers to the [[longitude of the ascending node]] of an orbit.

[[ko:Ω]]

* In [[mathematics]] and [[computer science]]:

[[it:Omega (lettera)]]

** In complex analysis, the [[Omega constant]], a solution of Lambert's W function<ref>{{Cite web |last=Weisstein |first=Eric W. |title=Omega Constant |url=https://mathworld.wolfram.com/OmegaConstant.html |access-date=2025-01-18 |website=mathworld.wolfram.com |language=en}}</ref>

[[he:אומגה]]

** In differential geometry, the space of [[differential form]]s on a [[manifold]] (of a certain degree, usually with a superscript).

[[la:Omega]]

** A variable for a 2-dimensional region in calculus, usually corresponding to the ___domain of a double integral.

[[nl:Omega (letter)]]

** In topos theory, the (codomain of the) [[subobject classifier]] of an elementary topos.

[[ja:Ω]]

** In [[combinatory logic#Undecidability of combinatorial calculus|combinatory logic]], the looping combinator, ''(S I I (S I I))''

[[nn:Omega]]

** In group theory, the [[omega and agemo subgroup]]s of a ''p''-group, Ω(''G'') and ℧(''G'')

[[nds:Omega]]

** In group theory, [[Cayley's Ω process]] as a partial differential operator.

[[pl:Omega (litera)]]

** In statistics, it is used as the symbol for the [[sample space]], or total set of possible outcomes.

[[pt:Ω]]

** In [[triangle geometry]], [[Brocard points]]<ref>{{Cite web |last=Weisstein |first=Eric W. |title=Brocard Points |url=https://mathworld.wolfram.com/BrocardPoints.html |access-date=2025-02-07 |website=mathworld.wolfram.com |language=en}}</ref>

[[ru:Омега (буква)]]

** In [[number theory]], [[Prime omega function|Ω(''n'')]] is the number of [[prime divisor]]s of ''n'' (counting [[Multiplicity (mathematics)|multiplicity]]).<ref>{{Cite web |last=Weisstein |first=Eric W. |title=Prime Factor |url=https://mathworld.wolfram.com/PrimeFactor.html |website=mathworld.wolfram.com |access-date=12 August 2020 }}</ref>

[[fi:Oomega]]

** In notation related to [[Big O notation]] to describe the asymptotic behavior of functions.

[[sv:Omega]]

** [[Chaitin's constant]].

[[zh:Ω]]

** In [[set theory]], the [[first uncountable ordinal|first uncountable ordinal number]], ω₁ or Ω

** The [[absolute infinite]] proposed by [[Georg Cantor]].

* As part of a logo or trademark:

** The logo of [[Omega Watches]] SA<ref>{{Cite web|url=https://www.hallandladdco.com/blogs/interesting-articles/the-history-of-the-omega-watch-company|title=The History Of The Omega Watch Company|website=HallandLaddco|language=en|access-date=2019-02-02|archive-date=March 19, 2020|archive-url=https://web.archive.org/web/20200319035901/https://www.hallandladdco.com/blogs/interesting-articles/the-history-of-the-omega-watch-company|url-status=dead}}</ref>

** Part of the original [[Pioneer Corporation|Pioneer]] logo<ref>{{Cite web |title=Pioneer Logo, symbol, meaning, history, PNG, brand |url=https://logos-world.net/pioneer-logo/ |access-date=2025-02-08 |language=en-US |quote=The logo features a tuning fork surrounded by the Greek letter Omega.}}</ref>

** Part of the [[Supreme Court of the United Kingdom|Badge of the Supreme Court]] of the United Kingdom<ref>{{Cite web |date=2022-05-07 |title=Emblem of the Supreme Court - Herald Art |url=https://heraldart.co.uk/emblem-of-the-supreme-court/ |access-date=2025-02-08 |language=en-GB |quote=The emblem shows the plant badges of England and Wales, Scotland and Northern Ireland surrounded by Omega the ultimate letter in the Greek alphabet.}}</ref>

** Part of the mission patch for [[STS-135]], as it was the last mission of the Space Shuttle program<ref>{{Cite web |title=STS-135 / Atlantis mission patch - collectSPACE: Messages |url=http://www.collectspace.com/ubb/Forum18/HTML/000805.html |access-date=2025-02-08 |website=www.collectspace.com |quote=Omega, the last letter in the Greek alphabet, recognizes this mission as the last flight of the space shuttle program.}}</ref>

** The logo of the ''[[God of War (franchise)|God of War]]'' video game series based on Greek mythology. In God of War (2018), it is revealed it stands as the symbol of war in Greece.

** The logo of [[E-123 Omega]], a ''[[Sonic the Hedgehog]]'' character.

** The logo of the [[Heroes of Olympus]] series, based on Greek mythology.

** the logo of the [[Space Marines (Warhammer 40,000)|Ultramarines]] in ''[[Warhammer 40,000]]''

** The logo of Primal Groudon, the version mascot of ''[[Pokémon Omega Ruby]]''.

** The logo of [[Darkseid]] in DC comics

** One of the logos of professional wrestler [[Kenny Omega]]

** The logo for [[Meow Wolf]]'s [[Omega Mart]] in Area15, Las Vegas, Nevada

** The logo of [[Lalaji Memorial Omega International School]]

[[File:Fachada de Panteón de la Cruz.jpg|thumb|Omega-shaped entrance to the Panteón de la Cruz in [[Aguascalientes (city)|Aguascalientes]], representing the end of life<ref>{{cite web |title=Desde la Revolución hasta el 2020 |url=https://www.aguascalientes.gob.mx/territoriojoven/revolucion2020 |website=Gobierno de Aguascalientes |access-date=7 August 2024 |quote=...su fachada representa a una omega que simboliza el final de la vida.}}</ref>]]

* Other:

** In [[eschatology]], the symbol for the end of everything

** In [[molecular biology]], the symbol is used as shorthand to signify a genetic construct introduced by a [[Crossover (genetic algorithm)#Two-point crossover|two-point crossover]]

** Omega Particle in the [[The Omega Directive|Star Trek universe]]<ref>{{Cite web |date=2013-10-16 |title=6 Ridiculous Sci-Fi Energy Schemes |url=https://www.popularmechanics.com/culture/g1338/6-ridiculous-sci-fi-energy-schemes/ |access-date=2025-02-07 |website=Popular Mechanics |language=en-US |quote=But the writers of one episode of Star Trek: Voyager apparently slept through that lecture, as they introduced the omega particle in "The Omega Directive."}}</ref>

** The final form of NetNavi bosses in some of the ''[[Mega Man Battle Network]]'' games

** A secret boss in the ''[[Final Fantasy]]'' series called Omega ( Ω ) Weapon.

** A character from the series ''[[Doctor Who]]'' called Omega, believed to be one of the creators of the Time Lords of Gallifrey.

** The symbol for the highest power level of a [[Psionics|PSI]] attack in the ''[[Mother (video game series)|Mother]]/[[EarthBound]]'' games

** A symbol used by U.S. citizens in the 1960s & 1970s to denote resistance to the U.S. war in Viet Nam. Adapted from the SI unit for electrical resistance.<ref>{{cite web | url=http://www.substancenews.net/articles.php?page=6592 | title=Resistance should begin now - Substance News }}</ref>

** It's used along with [[Alpha]] in the [[Alpha and Omega]], a Christian symbol.<ref>{{CathEncy|wstitle= A and Ω |volume= 1 |page= 332 |last= Hassett |first= M.M. |author-link= |year=1913|short= 1}}</ref>

** Used as the [[Rank|highest tier]] of equipment in the [[Browser game|flash game]], Learn to Fly

** Appears in [[Galaxy Quest|galaxy quest]] as the [[Omega 13 device]]

== The symbol ω (lowercase letter) ==

The [[Lower case|minuscule]] letter ω is used as a symbol:

* Biology, biochemistry and chemistry:

** In [[biochemistry]], for one of the [[RNA polymerase]] subunits

** In biology, for [[Fitness (biology)|fitness]]

** In [[chemistry]], for denoting the carbon atom furthest from the [[carboxyl group]] of a [[fatty acid]]

** In [[genomics]], as a measure of [[molecular evolution]] in protein-coding genes (also denoted as d_N/d_S or [[Ka/Ks ratio|K_a/K_s ratio]])

* Physics:

** [[Angular velocity]] or [[angular frequency]]<ref>{{Citation |last=Elert |first=Glenn |title=Special Symbols |date=2023 |work=The Physics Hypertextbook |quote= ω angular frequency|url=https://physics.info/symbols/ |access-date=2025-02-01 |publisher=hypertextbook |language=en}}</ref>

** Rotation velocity (bold), [[Rotational frequency|rotational speed or frequency]]<ref>{{Citation |last=Elert |first=Glenn |title=Special Symbols |date=2023 |work=The Physics Hypertextbook |quote= '''ω''', ω rotational velocity, rotational speed|url=https://physics.info/symbols/ |access-date=2025-02-01 |publisher=hypertextbook |language=en}}</ref>

** In [[computational fluid dynamics]], the specific turbulence dissipation rate

** In [[meteorology]], the change of pressure with respect to time of a [[Fluid parcel|parcel]] of air

** In [[circuit analysis]] and [[signal processing]] to represent [[angular frequency]], related to [[frequency]] ''f'' by ω = 2π''f''

** In [[astronomy]], as a ranking of a star's brightness within a constellation

** In [[orbital mechanics]], as designation of the [[argument of periapsis]] of an orbit

** In [[particle physics]] to represent the [[Meson|omega meson]]<ref>{{cite journal |last=Maglich |first=B. |date=1976 |title=Discovery of omega meson-first neutral vector meson: one researcher's account - Discovery story |url=https://inspirehep.net/files/bed57fc443ad4a089648fd0574f4d256 |journal=Advanced Experimental Physics |volume=5 |pages=79–105 |quote=Omega Meson Observed (page 97)}}</ref>

* Computer science:

** In notation related to [[Big O notation]], the [[Asymptotical dominance|asymptotically dominant]] nature of [[Function (mathematics)|functions]]

** In [[relational database]] theory to represent [[Null (SQL)|NULL]], a missing or inapplicable value

** In [[APL (programming language)|APL]], to represent the right parameter to a function

* Mathematics:

** The first and smallest [[Transfinite number|transfinite]] [[ordinal number]], often identified with the set of natural numbers including 0 (sometimes written <math>\omega_0</math>)<ref>{{Cite web |last=Weisstein |first=Eric W. |title=Ordinal Number |url=https://mathworld.wolfram.com/OrdinalNumber.html |access-date=2025-01-18 |website=mathworld.wolfram.com |language=en |quote=The first transfinite ordinal, denoted ω, is ...}}</ref><ref>{{Citation |last=Easwaran |first=Kenny |title=Infinity |date=2024 |work=The Stanford Encyclopedia of Philosophy |editor-last=Zalta |editor-first=Edward N. |url=https://plato.stanford.edu/entries/infinity/ |access-date=2025-02-07 |edition=Summer 2024 |publisher=Metaphysics Research Lab, Stanford University |last2=Hájek |first2=Alan |last3=Mancosu |first3=Paolo |last4=Oppy |first4=Graham |editor2-last=Nodelman |editor2-first=Uri}}</ref>

** In [[set theory]], ω is the [[ordinal number]]<ref>{{Cite web |title=first uncountable ordinal in nLab |url=https://ncatlab.org/nlab/show/first+uncountable+ordinal |website=NCatLab.org |access-date=12 August 2020 }}</ref>

** A primitive [[Roots of unity|root of unity]], like the complex cube roots of 1

** The [[Wright Omega function]]<ref>{{Cite web |last=Weisstein |first=Eric W. |title=Wright Function |url=https://mathworld.wolfram.com/WrightFunction.html |access-date=2025-01-18 |website=mathworld.wolfram.com |language=en}}</ref>

** A generic [[differential form]]

** In [[number theory]], ω(''n'') is the number of distinct [[prime divisor]]s of ''n''<ref>{{Cite web |last=Weisstein |first=Eric W. |title=Distinct Prime Factors |url=https://mathworld.wolfram.com/DistinctPrimeFactors.html |access-date=2025-02-08 |website=mathworld.wolfram.com |language=en |quote=The distinct prime factors of a positive integer n>=2 are defined as the ω(n) numbers p_1, ..., p_(ω(n))...}}</ref>

** In [[number theory]], an [[arithmetic function]]

** In [[combinatory logic]], the self-application combinator, ''(λ x. x x)''

** In [[triangle geometry]], a [[Brocard angle]]<ref>{{Cite web |last=Weisstein |first=Eric W. |title=Brocard Angle |url=https://mathworld.wolfram.com/BrocardAngle.html |access-date=2025-02-07 |website=mathworld.wolfram.com |language=en}}</ref>

** [[Clique number]] in [[Graph theory]]<ref>{{Cite web |last=Weisstein |first=Eric W. |title=Clique |url=https://mathworld.wolfram.com/Clique.html |access-date=2025-02-07 |website=mathworld.wolfram.com |language=en |quote=A clique of a graph G is a complete subgraph of G, and the clique of largest possible size is referred to as a maximum clique (which has size known as the (upper) clique number ?(G)).}}</ref>

* Finance:

** In finance, the elasticity of [[Option (finance)|options]]

** In analytical investment management, the [[tracking error]] of an investment manager

* Other:

** Used in place of [[N (kana)|ん]] in Japanese typing shorthand.

** In [[linguistics]], the [[phonological word]]

** In [[textual criticism]], the [[archetype]] of a manuscript tradition

** In [[sociology]], used to refer to the lowest ranking member of a group<ref>{{Cite web |title=Definition of Omega Male, BuzzWord from Macmillan Dictionary |url=https://www.macmillandictionary.com/buzzword/entries/omega-male.html |website=macmillandictionary.com |access-date=10 February 2021 }}</ref>

** In [[economics]] (specifically like in general equilibrium theory), the endowments of agents

** In [[shift_JIS art]], used to represent the cat's mouth. (e.g. {{lang|ja|(´･ω･`) ｼｮﾎﾞｰﾝ}})

** In [[Actuarial science|actuarial sciences]], used to represent the maximum life span that characterizes a [[mortality table]]<ref>{{Cite web |title=Life Table — Solving Actuarial Math with Python |url=https://actuarialmath-guide.readthedocs.io/en/latest/lifetable.html |access-date=2025-02-08 |website=actuarialmath-guide.readthedocs.io |quote=A life table, from some initial age x0 to a maximum age ω, represents a survival model with probabilities...}}</ref>

==Unicode==

* {{unichar|0277|html=}}<ref>Unicode Code Charts: [https://www.unicode.org/charts/PDF/U0370.pdf Greek and Coptic (Range: 0370-03FF)]</ref>

* {{unichar|038F|html=}}

* {{unichar|03A9|html=}}

* {{unichar|03C9|html=}}

* {{unichar|03CE|html=}}

* {{unichar|03D6|html=}}

* {{unichar|0460|html=}}

* {{unichar|0461|html=}}

* {{unichar|047A|html=}}

* {{unichar|047B|html=}}

* {{unichar|047C|html=}}

* {{unichar|047D|html=}}

* {{unichar|1F60|html=}}

* {{unichar|1F61|html=}}

* {{unichar|1F62|html=}}

* {{unichar|1F63|html=}}

* {{unichar|1F64|html=}}

* {{unichar|1F65|html=}}

* {{unichar|1F66|html=}}

* {{unichar|1F67|html=}}

* {{unichar|1F68|html=}}

* {{unichar|1F69|html=}}

* {{unichar|1F6A|html=}}

* {{unichar|1F6B|html=}}

* {{unichar|1F6C|html=}}

* {{unichar|1F6D|html=}}

* {{unichar|1F6E|html=}}

* {{unichar|1F6F|html=}}

* {{unichar|1F7C|html=}}

* {{unichar|1F7D|html=}}

* {{unichar|1FA0|html=}}

* {{unichar|1FA1|html=}}

* {{unichar|1FA2|html=}}

* {{unichar|1FA3|html=}}

* {{unichar|1FA4|html=}}

* {{unichar|1FA5|html=}}

* {{unichar|1FA6|html=}}

* {{unichar|1FA7|html=}}

* {{unichar|1FA8|html=}}

* {{unichar|1FA9|html=}}

* {{unichar|1FAA|html=}}

* {{unichar|1FAB|html=}}

* {{unichar|1FAC|html=}}

* {{unichar|1FAD|html=}}

* {{unichar|1FAE|html=}}

* {{unichar|1FAF|html=}}

* {{unichar|1FF2|html=}}

* {{unichar|1FF3|html=}}

* {{unichar|1FF4|html=}}

* {{unichar|1FF6|html=}}

* {{unichar|1FF7|html=}}

* {{unichar|1FFA|html=}}

* {{unichar|1FFB|html=}}

* {{unichar|1FFC|html=}}

* {{unichar|2375|html=}}

* {{unichar|2379|html=}}

* {{unichar|2CB0|html=}}

* {{unichar|2CB1|html=}}

* {{unichar|2CBE|html=}}

* {{unichar|2CBF|html=}}

* {{unichar|A64C|html=}}

* {{unichar|A64D|html=}}

* {{unichar|A67B|html=}}

* {{unichar|A7B6|html=}}

* {{unichar|A7B7|html=}}

* {{unichar|AB65|html=}}

* {{unichar|107A4|html=}}

* {{unichar|1D6C0|html=}}{{efn|The {{sc|mathematical}} characters are used only in math. Stylized Greek text should be encoded using the normal Greek letters, with markup and formatting to indicate the style of the text.}}

* {{unichar|1D6DA|html=}}

* {{unichar|1D6FA|html=}}

* {{unichar|1D714|html=}}

* {{unichar|1D734|html=}}

* {{unichar|1D74E|html=}}

* {{unichar|1D76E|html=}}

* {{unichar|1D788|html=}}

* {{unichar|1D7A8|html=}}

* {{unichar|1D7C2|html=}}

{{notelist}}

==References==

{{Reflist}}

==External links==

* {{Commons category-inline}}

* {{Wiktionary-inline|Ω|ω}}

[[Category:Greek letters]]

[[Category:Vowel letters]]