S: (n) linesman (official (in tennis, soccer, football, etc.) who assists the referee in some way (especially by watching for out of bounds or offside))
S: (n) referee, ref ((sports) the chief official (as in boxing or American football) who is expected to ensure fair play)
S: (adj) established, constituted (brought about or set up or accepted; especially long established) "the established social order"; "distrust the constituted authority"; "a team established as a member of a major league"; "enjoyed his prestige as an established writer"; "an established precedent"; "the established Church"