An appositive is a word or a phrase that means the same thing – or amplifies -- the word that immediately precedes it.
While many references consider only noun phrases to be appositives, others, such as Marcella Frank*, state that "the appositive can be any nominal structure used in the function of appositive: noun, pronoun, noun clause, infinitive phrase, etc." *
She goes on to say: "We are reserving the term ˜appositive phrase' only for those structures placed alongside nouns that are the equivalent of complements found in the predicate after the verb ˜be.' "
Some examples of appositive phrases under the larger definition:
"¢ I'd like you to meet my friend Robert, a world-class Scrabble player. (noun phrase)
"¢ Harriet is too old now even to partake in her favorite activity, shopping for clothes. (gerund phrase)
"¢ My goal -- to become president of this organization within three years – is a distinct possibility. (infinitive phrase)
"¢ Ms. Zither, in a great hurry, forgot to lock the classroom door and close the windows. (prepositional phrase)
Some examples of prepositional phrases as appositives in Modern English*:
"¢ The boy's mother, (who was) at a loss to know why he was crying, tried to console him.
"¢ The young man, (who is) madly in love with his employer's daughter, is afraid to ask her to marry him.
Some examples of "marked appositives" in The Cambridge Grammar of the English Language**:
"¢ She was born in the month of May.
"¢ It took place in the city of Berlin
Frank says: "The reader is probably more familiar with the term appositive as it is used for nouns standing after other nouns without a grammatical link." It is true that most explanations of "appositives" do relate to nouns or noun phrases, and that some of the above examples could fit other definitions, such as adjective phrase or adverb phrase.
*Modern English, Second Edition, by Marcella Frank. Regents Prentice Hall. 1993
**The Cambridge Grammar of the English Language, by Rodney Huddleston and Geoffrey K. Pullum. Cambridge University Press. 2002