Possessive determiners constitute a sub-class of determiners which modify a noun by attributing possession (or other sense of belonging) to someone or something. They are also known as possessive adjectives, although the latter term is sometimes used with a wider meaning.
Examples in English include possessive forms of the personal pronouns, namely: my, your, his, her, its, our and their, but excluding those forms such as mine, yours, hers, ours, and theirs that are used as possessive pronouns but not as determiners. Possessive determiners may also be taken to include possessive forms made from nouns, from other pronouns and from noun phrases, such as John's, the girl's, somebody's, the king of Spain's, when used to modify a following noun.
In many languages, possessive determiners are subject to agreement with the noun they modify, as in the French mon, ma, mes, respectively the masculine singular, feminine singular and plural forms corresponding to the English my.
Possessive determiners (possessive adjectives) have features of both determiners and adjectives:
While some classify the words my, your, etc. as possessive adjectives, others, due to the differences noted above, do not consider them adjectives – at least, not in English – and prefer possessive determiners. In some other languages the equivalent parts of speech behave more like true adjectives, however.
The words my, your, etc. are sometimes classified, along with mine, yours etc., as possessive pronouns or genitive pronouns, since they are the possessive (or genitive) forms of the ordinary personal pronouns I, you etc. However, unlike most other pronouns, they do not behave grammatically as stand-alone nouns, but instead qualify another noun – as in my book (contrasted with that's mine, for example, where mine substitutes for a complete noun phrase such as my book). For this reason, other authors restrict the term "possessive pronoun" to the group of words mine, yours etc. that substitute directly for a noun or noun phrase.