Old English Belzebub, Philistine god worshipped at Ekron (II Kings i.2), from Latin, used in Vulgate for New Testament Greek beelzeboub, from Hebrew ba'al-z'bub "lord of the flies," from ba'al "lord" (see Baal) + z'bhubh "fly." Said to have been worshipped as having the power to drive away troublesome flies. By later Christian writers often taken as another name for "Satan," though Milton made him one of the fallen angels.

Baal being originally a title, it was applied by the Hebrews to neighboring divinities based on their attributes; other examples include Baal-berith "the covenant lord," god of the Shechemites; Baal-peor "lord of the opening," a god of Moab and Midian.