Omega (US: /oʊˈmeɪɡə,-ˈmɛɡə,-ˈmiːɡə/ⓘ, UK: /ˈoʊmɪɡə/;[1] uppercase Ω, lowercase ω; Ancient Greek ὦ, later ὦ μέγα, Modern Greek ωμέγα) is the twenty-fourth and last letter in the Greek alphabet. In the Greek numeric system/isopsephy (gematria), it has a value of 800. The word literally means "great O" (o mega, mega meaning "great"), as opposed to omicron, which means "little O" (o mikron, micron meaning "little").[2]
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, in contrast to alpha, the first letter of the Greek alphabet; see Alpha and Omega.
History
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Ω was not part of the early (8th century BC) Greek alphabets. It was introduced in the late 7th century BC in the Ionian cities of Asia Minor to denote a longopen-mid back rounded vowel[ɔː]. It is a variant of omicron (Ο), broken up at the side (), with the edges subsequently turned outward (, , , ).[3] 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 /o/.[3]
The name Ωμέγα is Byzantine; in Classical Greek, the letter was called ō (ὦ) (pronounced /ɔ̂ː/), whereas the omicron was called ou (οὖ) (pronounced /ôː/).[4] The modern lowercase shape goes back to the uncial form , a form that developed during the 3rd century BC in ancient handwriting on papyrus, from a flattened-out form of the letter () that had its edges curved even further upward.[5]
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).
For oxygen-18, a natural, stable isotope of oxygen[6]
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.[7]
For ohm – SI unit of electrical resistance.[8] Unicode has a separate code point U+2126ΩOHM SIGN (HTML entityΩ), but it is included only for backward compatibility, and the canonically equivalent code point U+03A9ΩGREEK CAPITAL LETTER OMEGA (Ω) is preferred. Also formerly also used upside down (U+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.[9]
In statistical mechanics, Ω refers to the multiplicity (number of microstates) in a system.
The solid angle[10] or the rate of precession in a gyroscope
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 PSI attack in the 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.[20]
U+1D76E𝝮MATHEMATICAL SANS-SERIF BOLD CAPITAL OMEGA
U+1D788𝞈MATHEMATICAL SANS-SERIF BOLD SMALL OMEGA
U+1D7A8𝞨MATHEMATICAL SANS-SERIF BOLD ITALIC CAPITAL OMEGA
U+1D7C2𝟂MATHEMATICAL SANS-SERIF BOLD ITALIC SMALL OMEGA
^The 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.
References
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^Wells, John C. (2008). "omega". Longman Pronunciation Dictionary (3rd ed.). Longman. ISBN 978-1-4058-8118-0.
^ abAnne Jeffery (1961), The Local Scripts of Archaic Greece, pp. 37–38.
^Herbert Weir Smyth A Greek Grammar for Colleges §1.
^Edward M. Thompson (1912), Introduction to Greek and Latin Paleography, Oxford: Clarendon, p. 144.
^Capilla, José E.; Arevalo, Javier Rodriguez; Castaño, Silvino Castaño; Teijeiro, María Fé Díaz; del Moral, Rut Sanchez; Diaz, Javier Heredia (19 September 2012). "Mapping Oxygen-18 in Meteoric Precipitation over Peninsular Spain Using Geostatistical Tools" (PDF). cedex.es. Valencia, Spain: Ninth Conference on Geostatistics for Environmental Applications. Archived from the original (PDF) on 23 September 2015. Retrieved 8 May 2017.
^Krishna, Mallela M. G.; Lin, Yan; Rumbley, Jon N.; Walter Englander, S. (1 August 2003). "Cooperative Omega Loops in Cytochrome c: Role in Folding and Function". Journal of Molecular Biology. 331 (1): 29–36. doi:10.1016/S0022-2836(03)00697-1. ISSN 0022-2836.
^"Ohm | Electricity, Resistance & Voltage | Britannica". www.britannica.com. 3 January 2025. Retrieved 8 February 2025.
^Excerpts from The Unicode Standard, Version 4.0. Retrieved 11 October 2006.
^Weisstein, Eric W. "Solid Angle". mathworld.wolfram.com. Retrieved 7 February 2025. 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.
^Weisstein, Eric W. "Omega Constant". mathworld.wolfram.com. Retrieved 18 January 2025.
^Weisstein, Eric W. "Brocard Points". mathworld.wolfram.com. Retrieved 7 February 2025.
^Weisstein, Eric W. "Prime Factor". mathworld.wolfram.com. Retrieved 12 August 2020.
^"The History Of The Omega Watch Company". HallandLaddco. Archived from the original on 19 March 2020. Retrieved 2 February 2019.
^"Pioneer Logo, symbol, meaning, history, PNG, brand". Retrieved 8 February 2025. The logo features a tuning fork surrounded by the Greek letter Omega.
^"Emblem of the Supreme Court - Herald Art". 7 May 2022. Retrieved 8 February 2025. The emblem shows the plant badges of England and Wales, Scotland and Northern Ireland surrounded by Omega the ultimate letter in the Greek alphabet.
^"STS-135 / Atlantis mission patch - collectSPACE: Messages". www.collectspace.com. Retrieved 8 February 2025. Omega, the last letter in the Greek alphabet, recognizes this mission as the last flight of the space shuttle program.
^"Desde la Revolución hasta el 2020". Gobierno de Aguascalientes. Retrieved 7 August 2024. ...su fachada representa a una omega que simboliza el final de la vida.
^"6 Ridiculous Sci-Fi Energy Schemes". Popular Mechanics. 16 October 2013. Retrieved 7 February 2025. 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."
^Elert, Glenn (2023), "Special Symbols", The Physics Hypertextbook, hypertextbook, retrieved 1 February 2025, ω angular frequency
^Elert, Glenn (2023), "Special Symbols", The Physics Hypertextbook, hypertextbook, retrieved 1 February 2025, ω, ω rotational velocity, rotational speed
^Maglich, B. (1976). "Discovery of omega meson-first neutral vector meson: one researcher's personal account - Discovery story". Advanced Experimental Physics. 5: 79–105. Omega Meson Observed (page 97)
^Weisstein, Eric W. "Ordinal Number". mathworld.wolfram.com. Retrieved 18 January 2025. The first transfinite ordinal, denoted ω, is ...
^Easwaran, Kenny; Hájek, Alan; Mancosu, Paolo; Oppy, Graham (2024), Zalta, Edward N.; Nodelman, Uri (eds.), "Infinity", The Stanford Encyclopedia of Philosophy (Summer 2024 ed.), Metaphysics Research Lab, Stanford University, retrieved 7 February 2025
^"first uncountable ordinal in nLab". NCatLab.org. Retrieved 12 August 2020.
^Weisstein, Eric W. "Wright Function". mathworld.wolfram.com. Retrieved 18 January 2025.
^Weisstein, Eric W. "Distinct Prime Factors". mathworld.wolfram.com. Retrieved 8 February 2025. The distinct prime factors of a positive integer n>=2 are defined as the ω(n) numbers p_1, ..., p_(ω(n))...
^Weisstein, Eric W. "Brocard Angle". mathworld.wolfram.com. Retrieved 7 February 2025.
^Weisstein, Eric W. "Clique". mathworld.wolfram.com. Retrieved 7 February 2025. 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)).
^"Definition of Omega Male, BuzzWord from Macmillan Dictionary". macmillandictionary.com. Retrieved 10 February 2021.
^"Life Table — Solving Actuarial Math with Python". actuarialmath-guide.readthedocs.io. Retrieved 8 February 2025. A life table, from some initial age x0 to a maximum age ω, represents a survival model with probabilities...
^Unicode Code Charts: Greek and Coptic (Range: 0370-03FF)
External links
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Media related to Omega (letter) at Wikimedia Commons