Noun:(sports) the chief official (as in boxing or American football) who is expected to ensure fair play
ref的用法和样例：
例句
用作名词(n.)The game's not over till the ref blows the whistle.裁判吹响哨子，比赛才算结束。If I had been the ref I wouldn't have given a penalty then.如果我是裁判，那时候就不会罚犯规。The ref is placing the ball for a free kick to the visiting team.裁判员正在安排让客队罚任意球。