What is "assistant referee"

n. (context soccer British English): One of the two officials at an association football match, previously known as linesman, who assist the referee.

In association football, an assistant referee (known as a linesman or lineswoman before 1996) is an official empowered with assisting the referee in enforcing the Laws of the Game during a match. At most organised levels of football the match officiating crew consists of the referee and two assistant referees, with one assistant referee assigned to each touchline. The assistant referee's duties generally consist of judging when the ball has left the field of play – including which team is entitled to return the ball to play, judging when an offside offence has occurred, and advising the referee when an infringement of the Laws of the Game has occurred out of his or her view. Depending on the local match rules and the discretion of the referee, an assistant referee may also be responsible for various administrative tasks, for example managing substitutions, helping the referee control the players, or replacing the referee if he or she is unable to continue. The assistant referee functions in an advisory role, and all judgements made by an assistant referee may be overruled by the referee.

At higher levels of play the referee is also assisted by a fourth official. The fourth official's duties are usually administrative in nature and vary depending on the match rules and the discretion of the referee. Common duties for a fourth official may include managing technical areas and substitutions, maintaining a backup record of the score, and cautions and sendings off, and displaying information on substitutions and extra time to spectators. Depending on the local match rules, the fourth official may replace the referee or one of the assistant referees if they are unable to continue.