Nouns are words that name people, places, things, or ideas. There are different types of nouns including proper nouns, common nouns, singular nouns, plural nouns, count nouns, non-count nouns, abstract nouns, collective nouns, compound nouns, and possessive nouns. Possessive nouns show ownership and are formed by adding an apostrophe and sometimes an "s" to the singular or plural noun depending on whether it already ends in S.