Omega

In phonetic terms, the Ancient Greek Ω represented a long open-mid back rounded vowel , in contrast to omicron, which represented the close-mid back rounded vowel , and the digraph }}, which represented the long close back rounded vowel . In modern Greek, both omega and omicron represent the mid back rounded vowel . The letter omega is transliterated into a Latin-script alphabet as or simply .
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. Provided by Wikipedia