assistant referee
noun/əˌsɪstənt refəˈriː/
/əˌsɪstənt refəˈriː/
(also referee’s assistant
/ˌrefəriːz əˈsɪstənt/
/ˌrefəriːz əˈsɪstənt/
)- (in football (soccer)) the official name for a linesman (= an official who helps the referee, for example in deciding whether or where a ball has passed outside the field of play)
助理裁判（边线裁判员的正式名称）