Question

what is the best definition of an appositive?
a nonrestrictive phrase that modifies a noun
a clause that modifies or explains a noun
a noun or noun phrase that modifies a noun
a noun clause that restricts the meaning of a noun

Explanation:

An appositive is a grammatical element that is always a noun or noun phrase, and its function is to rename, identify, or modify another noun right next to it. It can be restrictive or nonrestrictive, so options limiting it to nonrestrictive phrases, clauses, or noun clauses are incorrect.

Answer:

a noun or noun phrase that modifies a noun