Boyd’s Bible Dictionary:
(great or long O). Last letter of Greek alphabet (Rev. 1:8).
Concise Bible Dictionary:
Ω ω
The last letter of the Greek alphabet: with Alpha, the first letter, it is descriptive of Jehovah as the beginning and the ending of all purpose concerning man (Rev. 1:8,11; Rev. 21:6; Rev. 22:13).
Strong’s Dictionary of Greek Words:
Meaning:
the last letter of the Greek alphabet, i.e. (figuratively) the finality
Jackson’s Dictionary of Scripture Proper Names:
finality last letter of Greek alphabet
Potts’ Bible Proper Names:
The last; the end; the last letter of the Greek alphabet, Rev. 1:8. {Extremus; finis}