An appositive or appositive phrase serves the function of replacing the noun in a sentence. It provides more information about the noun and can be found at the beginning, middle, or end of a sentence. Without the appositive, the meaning of the sentence will still be retained.
In the first sentence, the appositive, provides more information about the game winning hit. It was<em> a home run</em>. In the second sentence, <em>the plants by the hill side </em>offers further description of where the rose bush was situated.
