Words, or phrases, that refer to the same person or thing and have the same relationship to other sentence elements: In the sentence, "His friend, Martin, was a good student" the name "Martin" is in apposition to "His friend".

Relating to someone or something or an adjective directly following the noun it modifies: The "Tea Party", which is an appositive movement of conservatives in the United States, has been gaining more influence in political meetings.