- one of the running backs, typically smaller and faster than the fullback
- a defensive back, as a cornerback or safety
- a player positioned between the forwards and the fullbacks, who has both offensive and defensive responsibilities
- Football One of the running backs positioned to the sides behind the quarterback when the ball is snapped.
- Sports One of several players stationed behind the forward line, as in soccer or Rugby.
- (American football) An offensive back whose primary jobs are to carry the ball on running plays and to serve as a receiver or blocker on passing plays.
- (Canadian football) A defensive back whose primary jobs are to cover the slotback on passing plays and prevent running plays from going to the outside.
- (field hockey) A position in field hockey, with both offensive and defensive roles.