Linesman definition

(football) An official who marks the downs and the position of the ball and watches for certain violations from the sidelines.

An official in various court games whose chief duty is to call shots that fall out of bounds.

An official in soccer and other field games who indicates when the ball has gone out of bounds.

Either of two officials in ice hockey who call icing and offsides, conduct face-offs, and call penalities.

(tennis, soccer, etc.) An official who has the responsibility to make decisions along a sideline, goal line, etc., as in reporting whether the ball is inside or outside the line.

(soccer, dated) An assistant referee.

(American football) An official whose primary task is to determine whether there has been a line of scrimmage violation.