Omega (, ; 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"). In phonetic terms, the Ancient Greek Ω represented a long open-mid back rounded vowel, comparable to the "aw" of the English word raw in dialects without the cot–caught merger, in contrast to omicron which represented the close-mid back rounded vowel , and the digraph ου which represented the long close-mid back rounded vowel. In Modern Greek, both omega and omicron represent the mid back rounded vowel or. The letter omega is transliterated into a Latin-script alphabet as ō or simply o. 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

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 long open-mid back rounded vowel. It is a variant of omicron (Ο), broken up at the side, with the edges subsequently turned outward. 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. 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/). 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. In addition to the Greek alphabet, Omega was also adopted into the early Cyrillic alphabet (see Cyrillic omega (Ѡ, ѡ)). A Raetic variant is conjectured to be at the origin or parallel evolution of the Elder Futhark ᛟ. 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 (uppercase letter)

The uppercase letter Ω is used as a symbol:

The symbol ω (lowercase letter)

The minuscule letter ω is used as a symbol:

Unicode