Possessive Nouns. A possessive noun is a noun that names who or what has something. The possessive form is used with nouns referring to people, groups of people, countries, and animals. It also refers to where someone works or plays or spends their time.Add an apostrophe and s ('s) to form the possessive of most singular nouns (ex.ossessive Nouns. A possessive noun is a noun that names who or what has something. The possessive form is used with nouns referring to people, groups of people, countries, and animals. It also refers to where someone works or plays or spends their time.