A possessive pronoun is a type of pronoun that shows ownership or possession. It is used to indicate that something belongs to someone or something else. Possessive pronouns eliminate the need to use a noun and the possessive form of the noun together. Instead, they stand alone to indicate ownership. 

The most common possessive pronouns in English are:

1. Mine: Used to indicate that something belongs to the speaker.

Example: "The book is mine."

2. Yours: Used to indicate that something belongs to the person or people being spoken to.

Example: "Is this pen yours?"

3. His: Used to indicate that something belongs to a male.

Example: "The dog is his."

4. Hers: Used to indicate that something belongs to a female.

Example: "The car is hers."

5. Its: Used to indicate that something belongs to a thing or an animal.

Example: "The cat is grooming its fur."

6. Ours: Used to indicate that something belongs to a group the speaker is a part of.

Example: "The victory is ours."

7. Theirs: Used to indicate that something belongs to a group of people or things.

Example: "The keys are theirs."

These pronouns can be used to replace nouns in sentences to show possession or ownership.