Boyd’s Bible Dictionary:
Gathite followers of David
(2 Sam. 15:18-19). [GATH.]
Concise Bible Dictionary:
Designation of the six hundred men as inhabitants of Gath, and of their leader Ittai, who followed David at Absalom’s revolt (2 Sam. 15:18-22; 2 Sam. 18:2). Goliath also was a Gittite (2 Sam. 21:19; 1 Chron. 20:5). Obed-edom, though a Levite, was also called a Gittite, probably because of residing at Gath or Gath-rimmon (2 Sam. 6:10-11; 1 Chron. 13:13).
Jackson’s Dictionary of Scripture Proper Names:
gentilic of Gath