Purposes, functions (4)
I believe the answer is:
uses
This clue is a double definition.
'purposes' is the first definition.
(I know this)
'functions' is the second definition.
(I know this)
(Other definitions for uses that I've seen before include "Utilises" , "Functions, applications" , "Employments" , "Puts to a particular purpose" , "Purposes; consumes" .)