determiner

A determiner is a word that introduces a noun and helps specify its reference in a noun phrase. Determiners mark aspects such as definiteness, quantity, possession, and other contextual features that identify the noun’s reference to speakers and listeners. They typically appear before the noun and any adjectives within the phrase.

English uses several subtypes of determiners. These include: articles (the definite article the; the indefinite articles a and an); demonstratives (this, that, these, those); possessives (my, your, his, her, its, our, their); quantifiers (some, any, many, few, all, enough, more, most, both, either, neither, every, each); numerals that function as determiners (one, two, three); and interrogatives (which, what). In practice, a noun phrase such as the old man, this book, my car, some students, or which chair shows how determiners interact with adjectives and the noun to form a complete reference.

Determinants are a closed class in many languages and typically precede adjectives and the noun within a noun phrase. They help determine whether the listener can identify the referent and, in many cases, how many items are being referenced. Some languages do not have a distinct determiner system and instead rely on context or other grammatical markers to convey definiteness or quantity. Determiners contrast with adjectives, whose primary function is to describe properties of the noun rather than to fix its referent.