Depending on the use of the noun in a sentence it can also be classified into one of the following cases...

• Nominative Case
• Accusative Case
• Possessive Case

When a noun or a pronoun is used as a subject of a verb, it is in the Nominative Case.

The noun is said to be in the Accusative Case, if it is used as the object of a verb in the sentence.

When the noun is denotes with an 's (eg Gajen's book, mother's pen) to denote ownership or possession it said to be in the Possessive Case.