(American football) The official who stands behind the line on the defensive side.
(Australian rules football) A match official on the ground deciding and enforcing the rules during play. As of 2007 the Australian Football League uses 3, or in the past 2 or just 1. The other officials, the goal umpires and boundary umpires, are normally not called just umpires alone.
(law) A person who arbitrates between contending parties