a part of an army or military force detached from the main body to bring up and guard the rear from surprise attack, especially in a retreat.
The capelin rear guard, sensing danger, rose off the bottom in a great fleeing cloud.
The lieutenant with the rear guard concluded the train.
These forklifts did not have a protective rear guard or corner post to prevent under-ride from occurring.
Marion followed and destroyed the rear guard as they attempted to cross the river.
The marines formed the rear guard of the retreat, in which they were pursued for four hours.