Determiner

In linguistics, a determiner (abbreviated DET) is a word which adds information to a noun. It gives information about the context of the noun. A determiner may show whether the thing described is definite or indefinite, closer or more distant, singular or plural, etc. 
Common kinds of determiners include definite and indefinite articles (like the English "the" and "a" or "an"), demonstratives ("this" and "that"), possessives ("my" and "their"), quantifiers ("many", "few" and "several"), numerals ("three, twenty"), and interrogatives ("which").