Gog = "mountain"
1) the king of the land of Magog who will come from the north and attack the land of Israel
Part of Speech: noun proper locative
Citing in TDNT: 1:789, 136
Of Hebrew origin [H1463]; Gog, a symbolic name for some future Antichrist: - Gog.
These two sites give similar information, with the definition from several dictionaries and statistics on the use of the word.
Perseus Digital Library
University of Chicago's Logion lexicon
Thayer's dictionary plus other information.
From this site's dictionary (in Italian)
Click on the first column to search for that word as a form of the root Γώγ; click on the second column to search for that grammatical form of the root Γώγ; click on the third column to search for that word and grammatical form; click on the total to search for the root Γώγ.