Source : Webster's Revised Unabridged Dictionary (1913)

Omega \O*me"ga\, n. [NL., fr. Gr. ?, i.e., the great or long o.
   Cf. {Mickle}.]
   1. The last letter of the Greek alphabet. See {Alpha}.

   2. The last; the end; hence, death.

            ``Omega! thou art Lord,'' they said.  --Tennyson.

   {Alpha and Omega}, the beginning and the ending; hence, the
      chief, the whole. --Rev. i. 8.

            The alpha and omega of science.       --Sir J.
                                                  Herschel.

Source : WordNet®

omega
     n 1: the ending of a series or sequence; "the Alpha and the
          Omega, the first and the last, the beginning and the
          end"--Revelation [syn: {Z}]
     2: the last (24th) letter of the Greek alphabet

Source : Free On-Line Dictionary of Computing

Omega
     
        1.  A {prototype}-based {object-oriented}
        language from Austria.
     
        ["Type-Safe Object-Oriented Programming with Prototypes - The
        Concept of Omega", G. Blaschek, Structured Programming
        12:217-225, 1991].
     
        2.  A successor to {TeX} extended to handle the
        {Unicode} character set.
     
        {(http://www.ens.fr/omega/)}.
     
        (1997-11-20)