Noun (noun)

1. A word (other than a pronoun) used to identify any of a class of persons, places, things, or ideas.
2. A word or words naming an entity such as a person, place, thing, quality, or action.

Origin:

Late middle english: from old french noune, from latin nomen, noun- "name".

Examples:

1. The noun in the sentence is "book".
2. The noun phrase "the red car" refers to a specific car.
3. Nouns can be singular or plural.
4. Nouns are often used with articles and adjectives to form noun phrases.
5. Nouns can be used as the subject or object of a sentence.