Aide or Aid?
Exemple : ‘’He works as an aide to the president.’’
"Aide" and "aid" are homonyms as they are pronounced in exactly the same way although they have different uses. An "aide" is someone who works as an assitant usually in a political or military context.
Exemple : ‘’My grandmother wears a hearing aid.’’
"Aid" can be used as a verb as a synonym of the verb "help" and also as a noun in the same way as "help" can be used as both a verb and a noun.