- Football one of the running backs, used typically for blocking
- a defensive player who generally plays back in the defensive end of the field near the goal so as to prevent the opponent's forwards from scoring
- Football An offensive backfield player whose position is behind the quarterback and halfbacks and who primarily performs offensive blocking and line plunges.
- Sports A primarily defensive backfield player in field hockey, soccer, or Rugby whose position is near the defensive goal or goal line.
- (soccer) A player who plays on the left or right side of defence.
- (rugby) The player who wears the number 15 jersey at the start of play. The last line of defence responsible for catching punts.