A noun is a name of something, some person or somewhere. There are four types of noun:
Collective noun: the name of a group of animals. For example herd is a collective noun.
common noun: the name of an object or item. They don't usually have capital letters. For example book is a common noun.
Proper noun: the name of some person or place. They are nouns with all the capital letters. For example England is a proper noun, and Tom is a proper noun too.
Abstract noun: The feeling or emotion of something however you cannot touch it, hold it. For example, happiness is an abstract noun.