Noun is a word used as the name of a person, place or thing. There are several types of nouns including common nouns, proper nouns, singular nouns, plural nouns, possessive nouns, concrete nouns, and abstract nouns. Nouns can also serve different functions in a sentence such as subject, direct object, indirect object, predicate nominative, object of preposition, appositive, objective complement, retained object, and noun of direct address.