Definition of umpiring:
(n) :
An official who presides over a sports match.
(n) :
(cricket) One of the two white-coated officials who preside over a cricket match.
(n) :
(baseball) One of the officials who preside over a baseball game.
(n) :
(tennis, badminton) The official who presides over a tennis match sat on a high chair.
(n) :
(American football) The official who stands behind the line on the defensive side or next to the referee on the offensive side.
(n) :
(Australian rules football) A match official on the ground deciding and enforcing the rules during play. As of 2007 the Australian Football League uses three; in the past there were two or just one. The other officials, the goal umpires and boundary umpires, are usually referred to by those phrases.