Alpha, the first letter of the Greek alphabet, as Omega is the last. These letters occur in the text of Rev. 1:8, 11; 21:6; 22:13, and are represented by "Alpha" and "Omega" respectively (omitted in R.V., 1:11). They mean "the first and last." (Comp. Heb. 12:2; Isa. 41:4; 44:6; Rev. 1:11, 17; 2:8.) In the symbols of the early Christian Church these two letters are frequently combined with the cross or with Christ's monogram to denote his divinity.
Easton's Bible Dictionary. M.G. Easton. 1897.