It means either one or two whichever one you want to use:
1. determine number or extent of something: to calculate or express the number, degree, or amount of something 2. show range of reference of something: to use a quantifier to limit the range of individuals or items referred to in a sentence or proposition
Peace on Rock out,
Amad That is the quantify's definition so it would means to be able to determine number or extent of something. Understand?