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Omega

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Look up Ω, ω in Wiktionary, the free dictionary.

Greek alphabet

Α α Alpha	Ν ν Nu
Β β Beta	Ξ ξ Xi
Γ γ Gamma	Ο ο Omicron
Δ δ Delta	Π π Pi
Ε ε Epsilon	Ρ ρ Rho
Ζ ζ Zeta	Σ σ ς Sigma
Η η Eta	Τ τ Tau
Θ θ Theta	Υ υ Upsilon
Ι ι Iota	Φ φ Phi
Κ κ Kappa	Χ χ Chi
Λ λ Lambda	Ψ ψ Psi
Μ μ Mu	Ω ω Omega
Obsolete letters
Ϝ ϝ Digamma	Ϻ ϻ San
Ϙ ϙ Qoppa	Ϡ ϡ Sampi
Ϛ ϛ Stigma	Ϸ ϸ Sho

Note: This article contains special characters.

For other uses, see Omega (disambiguation).

Omega (Ω ω) is the 24th and last letter of the Greek alphabet. In the Greek numeric system it has a value of 800. The word literally means "great O" (ō mega, mega meaning 'great'), as opposed to Omicron, which means "little O" (o mikron, micron meaning 'little').<ref>The Greek Alphabet</ref> This name is Byzantine; in Classical Greek, the letter was called ō (ὦ), whereas the Omicron was called ou (οὖ).<ref>Herbert Weir Smyth. A Greek Grammar for Colleges. §1</ref>

The form of the letter derives from a double omicron, which came to be written open at the top.

Phonetically, the Ancient Greek Ω is a long o, similar to the vowel of English close. It is transcribed ō or simply o. In Modern Greek Ω is a short o similar to the vowel of British English pot.

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. In the Bible, God declares himself to be the "Alpha and Omega, the beginning and the end, the first and the last".<ref>Revelation 22:13, KJV, and see also 1:8, Greek ἐγὼ τὸ ἄλφα καὶ τὸ ὦ, ὁ πρῶτος καὶ ὁ ἔσχατος, ἡ ἀρχὴ καὶ τὸ τέλος.</ref>

Omega was also adopted into the early Cyrillic alphabet. See omega (Cyrillic) (Ѡ, ѡ). A Raetic variant is at the origin of Elder Futhark ᛟ.

[edit] The symbol Ω (upper case letter)

The upper-case letter Ω is used as a symbol, it is also used often outside its Greek alphabetical context in literature, advertising and other forms of human expression.

For 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 with symbol S) used for electrical conductance. Unicode has a separate code point for the ohm sign (U+2126, Ω), but it is only included for backwards compatibility and the Greek uppercase omega character (U+03A9, Ω) is preferred.<ref>Excerpts from the The Unicode Standard, Version 4.0, accessed 11 October 2006</ref>
In computer science, in notation related to Big O notation to describe the asymptotic behavior of functions. See also Chaitin's constant
In mathematics, the Omega constant, a solution of Lambert's W function; or the first uncountable ordinal number (also known as <math>\omega_1</math>)
In physics, the solid angle.
In particle physics to represent the Omega baryons. A lowercase omega is used for the omega mesons.
In combinatory logic, the looping combinator, (λ x. x x) (λ x. x x)
In astronomy (cosmology) Ω refers to the density of the universe, also called the density parameter.
In automobiles, the 1983 Oldsmobile Omega.