(n) :
a class of words, with the main function of
determiner in a
noun phrase. Words in the determinative class usually also have other functions. Its core members include
articles and other items that fill the same slot as articles but are mutually exclusive with them, such as
cardinal numbers.
[determiner in The Cambridge Grammar of the English Language Huddleston & Pullum, 2002. CUP.] Examples include: the, this, most, any, three, etc