A topic sentence always states the main idea of a paragraph. A noun is a word that names a person, place, thing, or idea. Singular and Plural Nouns - Proper and Common Nouns Nouns can be singular or plural. A singular noun names one person, place, thing, or idea. A plural noun names more than one.
Nouns can be proper or common.
A proper noun names a particular person, place, thing, or idea. The names of days, months, holidays, organizations, and nationalities are proper nouns. All other nouns are common nouns. A possessive noun shows who or what owns something. There are rules to help make nouns possessive.