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'
(..) Well, if you absolutely have to do something vague... ...feel free to go where you wish. I can't take you to Bizu, but I can take you to Monsieur Vainqueur... ...the team's assistant coach. Well, I guess he's the head coach now. - You wanted to see me? - You are Vainqueur? Yes. And who are you? (..)1976 The Pink Panther Strikes Again