Rereward

(Josh 6:9), the troops in the rear of an army on the march, the rear-guard. This word is a corruption of the French arriere-garde. During the wilderness march the tribe of Dan formed the rear-guard (Num 10:25; comp. 1 Sam 29:2; Isa 52:12; Isa 58:8).

From Easton’s Bible Dictionary (1897), by Matthew George Easton.