linesman

noun

1. An assistant referee.

   “A linesman replaced injured referee Rebecca Welch after 50 minutes and with no other official present, qualified referee Pattison, 60, ran the line.”

   “As the linesman raised his flag, Neville played on, crossing for Piovaccari to net.”

2. (dated)A male line judge.
3. An official whose primary task is to watch the blue line and determine when there has been an offside.
4. An official whose primary task is to determine whether there has been a line of scrimmage violation.
5. A person employed to work on electrical lines; a lineman.
6. A private in the line.