This document defines and discusses different types of nouns. It explains that a noun is a word that names a person, place, thing, or idea. Nouns can play the role of subject in a sentence. The document distinguishes between common nouns and proper nouns. Common nouns are general words for people, animals, places, or things, while proper nouns specifically name a particular person, place, or thing. It provides examples of common nouns for people such as actor, cook, lawyer, police, aunt, judge, baby, man, baker, soldier, nurse, and teacher.