1. omega (plural omegas or omegala) The twenty-fourth letter of the Classical and the Modern Greek alphabet, and the twenty-eighth letter of the Old and the Ancient Greek alphabet, i.e. the last letter of every Greek alphabet. Uppercase version: Ω; lowercase: ω.  

2. (idiomatic, often capitalized) The end; the final, last or ultimate in a sequence.   I am the Alpha and the Omega, the First and the Last, the Beginning and the End. — Revelation 22:13, New International Version.

3. (physics) Angular velocity; symbol: ω.