Easton's Bible Dictionary: M. G. Easton, M.A., D.D.
Little fish; diminutive from dag = a fish, the fish-god; the national god of the Philistines (Judg. 16:23). This idol had the body of a fish with the head and hands of a man. It was an Assyrio-Babylonian deity, the worship of which was introduced among the Philistines through Chaldea. The most famous of the temples of Dagon were at Gaza (Judg. 16:23-30) and Ashdod (1 Sam. 5:1-7).