| Definition -
An adjective that shows ownership or possession, e.g. my, thy, his, her, its, our, your, and their.
1. Pronouns that show possession — such as mine, ours, and theirs — are called possessive pronouns.
Example - This is my Bud.
Oxford English Dictionary - The term's first citation is from 1870:
"The New Teutonic pronouns take the inflexions of the strong declension of the adjective, where they are used as possessive adjectives, as Germ. mein, meine, mein, gen. meines, meiner, meines."
(Helfenstein Comp. Gram. Teut. Lang. 199)