Nouns are words that name people, places, things, or ideas. Nouns can function as subjects, direct objects, indirect objects, subject complements, object complements, appositives, adjectives, or adverbs in a sentence. There are different types of nouns including countable, uncountable, singular, plural, concrete, abstract, common, proper, and collective nouns. An example paragraph demonstrates the use of various nouns like pen, book, sugar, oil, fruits, chocolate, sister, house, and Rani.