A possessive pronoun is a word that attributes ownership to someone or something without using a noun. For example, in the phrase,
These are my glasses, not yours, the word my is a determinative possessive pronoun, and yours is an independent possessive pronoun. The equivalent of the possessive pronoun is a pronoun in the genitive case in some languages, e.g. Finnish minun "I's" = my.
Pronouns are used to refer to the two sides of a dialogue (I, my, mine, we, our, ours; you, your, yours) or to
reduce repetition:
`Julia called Julia's father, because Julia wanted to know whether Julia could use Julia's father's car'.
is more compactly expressed as
`Julia called her father, because she wanted to know whether she could use his car'.
Determinative possessive pronouns
There are seven of these in modern English: my, your, his, her, its, our, their
Older forms of English had one more: thy (`your') as in Thy kingdom come. It was used in familiar address, i.e., speech directed toward someone with whom one had a very close, perhaps family, relationship. Now this form only appears in poetic or religious use.
These possessive pronouns are called determinative because they constitute determiner phrases.
Note: Determinative possessive pronouns may also be called "possessive adjectives".
Independent possessive pronouns
There are seven of these in modern English: mine, yours, his, hers, its, ours, theirs
Older forms of English had one more: thine (`yours') as in All glory and honor be Thine. Like "thy," this form currently appears only in poetic and religious contexts.
These possessive pronouns are called independent, because they constitute full noun phrases and don't depend on a noun, i.e. while my must be followed by a noun such as glasses in my glasses, mine already subsumes such a noun.
Note: If determinative possessive pronouns are called "possessive adjectives", then independent possessive pronouns are referred to as simply "possessive pronouns".
For more information, see pronoun, noun, and possessive case