Theater worker
'theater worker' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for usher that I've seen before include "Court or parliamentary official" , "Person who shows one to a seat" , "Doorkeeper; shower to seat" , "Doorkeeper in parliament or 29 down" , "Show in - escort" .)
(Other definitions for projectionist that I've seen before include "Cinema employee" , "Cinema worker" .)