a dental 'assistant' [=a person whose job is to help a dentist]
She works as a 'sales assistant' [='salesclerk'] at Macy's.
a wealthy executive who has a personal 'assistant'
(..) - We can always use a good judge. - Thanks. Andrew! My godson Andrew Hagen. My brother Tom's eldest boy. He's been assistant to Bishop Breelan for three years. - Hopes to be assigned to the Vatican. - Rome needs fine young priests. His mother Theresa Hagen, Bishop Gilday. Honoured to meet you. (..)1990 The Godfather Part III