ref·e·ree 
(rĕf′ə-rē)
(rĕf′ə-rē)n.
1. One to whom something is referred, especially for settlement, decision, or an opinion as to the thing's quality.
2. Sports & Games An official supervising the play; an umpire.
3. Law A person appointed by a court to assist a judge in the trying of a case or to hear certain types of cases.
v. ref·e·reed, ref·e·ree·ing, ref·e·rees
v.tr.
To judge as referee.
v.intr.
To act as referee.