An appositive is a noun or pronoun, often with modifiers, set beside another noun or pronoun to explain or identify it.

Your friend Bill is in trouble. (Appositive= Bill)

My brother’s car, a sporty red convertible with bucket seats, is the envy of my friends. (Appositive= a sporty red convertible with bucket seats)

The chief surgeon, an expert in organ-transplant procedures, took her nephew on a hospital tour. (Appositive= an expert in organ-transplant procedures)

An appositive phrase usually follows the word it explains or identifies, but it may also precede it.

A bold innovator, Wassily Kandinsky is known for his colorful abstract paintings. (Appositive= A bold innovator)

The first state to ratify the U. S. Constitution, Delaware is rich in history. (Appositive= The first state to ratify the
U. S. Constitution)

SOURCE: Purdue Online Writing Center