Nouns are words that name people, places, things, or ideas. There are different types of nouns including abstract nouns which name ideas that cannot be seen, collective nouns which refer to groups, common nouns which are general names that are not capitalized, and proper nouns which are specific names that are always capitalized. Nouns can also be plural or singular depending on whether they refer to one or more than one item, and possessive nouns show ownership or a relationship between items.