the troops in the rear of an army on the march, the rear-guard (Joshua 6:9)

This word is a corruption of the French arriere-garde. During the wilderness march the tribe of Dan formed the rear-guard (Numbers 10:25; compare 1 Samuel 29:2; Isaiah 52:12).

Translated from the Hebrew 'acaph (a primitive root meaning to gather for any purpose; hence to receive, take away, i.e. remove (destroy, leave behind, put up, restore, etc.); withdraw.