Emily Dickinson Lexicon

REAR, n. [Fr. arriere; but this is compound; Arm. refr, rever, reor, the seat, the fundament; W. rhêv, something thick, a bundle; rhevyr, the fundament. Rear is contracted from rever. Class Rb.]

1. In a general sense, that which is behind or backward appropriately, the part of an army which is behind the other, either when standing on parade or when marching also, the part of a fleet which is behind the other. It is opposed to front or van. Bring up the rear.
2. The last class; the last in order. Coins I place in the rear. – Peacham. In the rear, behind the rest; backward, or in the last class. In this phrase, rear signifies the part or place behind.