Cases of word usage

1) (of a judge, referee etc) to give a judgment or decision (about something) (adjudicate)

2) a person who helps the umpire or referee by saying whether the ball crosses a line (linesman)

3) a (usually long) tuneful sound made by forcing air or stream through a small opening (e.g. the mouth, a bird's beak) or made by the wind; a simple instrument making a similar sound as used by a referee in games and sports (whistle)