What is the possessive of the phrase teacher aid?

Answer 1

The correct possessive compound noun is teacher's aide.

A possessive noun is used to show ownership, possession, origin, or purpose.

The noun teacher's in this compound noun is indicating purpose, an aide to assist the teacher.

NOTE:

The noun 'aid' is a word for for help or assistance, an abstract noun.

The noun 'aide' (with the 'e' at the end) is a word for a person.

Answer 2

It should be pointed out that "teacher aid" would never be used. The possessive would always be the correct term: teacher's aide. Note that here the word is spelled aide. An aide is a person; aid is assistance, usually financial or material such as supplies. The type of "aid" (financial or material) is often not stated, but often can be inferred from the context.

Despite receiving no salary, the teacher's aid regularly sent aid for school children in Africa.

Answer 3

The possessive form of "teacher aid" is "teacher aid's."