Introduction: Determiners are words like the, an, my, some. They are grammatically similar. They all come at the beginning of noun phrases, and usually we cannot use more than one determiner in the same noun phrase.
Determiners are different to pronouns in that a determiner is always followed by a noun. Therefore personal pronouns (I, you, he, etc.) and possessive pronouns (mine, yours, his, etc.) cannot be determiners.
The definite and indefinite articles a, an and the are all determiners.
List of Different Determiners