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'
(..) Easy, peasy, Japanese-y. -Any questions? -How long have you been librarian? I come here in ', and they made me librarian in . And have you ever had an assistant? No. Not much to it, really. Why me? Why now? I don't know. But it'd be nice to have some company down here. (..)1994 The Shawshank Redemption