A common noun is a noun that refers to a general class of things, such as a dog, a tree, or a book.

A proper noun is a noun that refers to a specific person, place, thing, or idea, such as Fido, The White House, or Love.

A collective noun is a noun that refers to a group of things, such as a pack of dogs, a herd of cows, or a flock of birds.

An abstract noun is a noun that refers to a concept or idea, such as love, hate, or beauty.

The nominative case is the case of a noun that is the subject of a verb.

The genitive case is the case of a noun that shows possession.

The dative case is the case of a noun that shows indirect object.

The accusative case is the case of a noun that is the direct object of a verb.

The ablative case is the case of a noun that shows separation or origin.

The plural form of a noun is the form that is used when referring to more than one of the thing that the noun names.

The singular form of a noun is the form that is used when referring to only one of the thing that the noun names.

Some nouns are always singular, even when they refer to more than one of the thing that they name. Fish is one such noun.

Some nouns are always plural, even when they refer to only one of the thing that they name. Scissors is one such noun.

A school is a collective noun that refers to a group of fish.

A flock is a collective noun that refers to a group of sheep.