Why is the ninth month called September?
c.1300, from Old French embuscher (13c., Modern French embûcher) "to lay an ambush," from en- "in" + busch "wood," apparently from Frankish *busk "bush, woods" (see bush (n.)). Related: Ambushed; ambushing.
late 15c., embushe, from the English verb or from Middle French embusche, from Old French embuscher (see ambush (v.)). Earlier was ambushment (late 14c.). Figurative use by 1590s.
Joshua at the capture of Ai lay in ambush, and so deceived the inhabitants that he gained an easy victory (Josh. 8:4-26). Shechem was taken in this manner (Judg. 9:30-45. Comp. Jer. 51:12).