Lexical Definition

‎Ω‎ Ō (o'-meg-ah) Omega ^G:N-LI
Omega.

• the last letter of the Greek alphabet, i.e. (figuratively) the finality

Abbott-Smith

Ω, ω, ὦ μέγα (cf. ὂ μικρόν),
omega, ô, the twenty-fourth and last letter. As a numeral, ωʹ = 800, ω͵ = 800,000. As a symbol of the last (= τὸ τέλος), τὸ Ὦ (Rec. Ω, L, ὦ, T, ω), the Omega: Re 1:8 21:6 22:13 (cf. Ἄλφα).†

Abbott-Smith References

Liddell-Scott-Jones

ω, Ὦμέγα, ὦ, τό,

twenty-fourth and last letter of the Ionic alphabet, ἀπὸ ἄλφα ἕως.ω. [Refs 9th c.AD+]; thence used as a symbol of the end, the last, ἐγώ εἰμι τὸ ἄλφα καὶ τὸ ὦ (not τὸ ὦ μέγα) [NT]:—as a numeral ώ = 800, but ωνυμ = 800, 000. The epichoric _Attic dialect_ and other alphabets of the Inscrr. had used o in differently to represent the sounds of the later ο and ω: ω, Ὦμέγα is a differentiated form of ο, and, though usually = ω, was used in the Ionic islands of Paros, Thasos, and Siphnos with the value ο, while O or O represented the sound ω. The name of the letter was τὸ ὦ (perispomenon accusative to [Refs 5th c.BC+]: after the loss of the distinction between long and short vowels, ο and ω had the same pronunciation; they begin to be confused in Papyri of Refs 3rd c.BC+

_{LSJ Scripture Refs: Rev.1.8}