also: awayside · back side
The half of the formation the play is going away from. Its assignments often stop pursuit, while pulls and misdirection can also begin there.
The side away from the point of attack, defined by where the ball is going rather than by left and right. The same lineman is backside on one call and frontside on the next without moving.
Many backside assignments are about cutting off pursuit rather than creating the initial running lane. The blocker may only need to get his body between a chasing defender and the ball. Other schemes pull a backside lineman or build the play around action that starts away from the point of attack.
awaysideweakside, boundary, frontsideBackside names a relationship to the play, not a low-value assignment. A backside guard may pull on Trap or Counter, and backside action often supplies the misdirection that holds pursuit.