Determiners
Linguists today distinguish determiners from adjectives, considering them to be two separate parts of speech (or lexical categories), but formerly determiners were considered to be adjectives in some of their uses. In English dictionaries, which typically still do not treat determiners as their own part of speech, determiners are often recognizable by being listed both as adjectives and as pronouns. Determiners are words that are neither nouns nor pronouns, yet reference a thing already in context. Determiners generally do this by indicating definiteness (as in a vs. the), quantity (as in one vs. some vs. many), or another such property.
Read more about this topic: Adjective