End use (7)
I believe the answer is:
purpose
I believe this is a double definition.
'end' is the first definition.
(end can mean a purpose or goal)
'use' is the second definition.
(something's purpose is its use or function)
(Other definitions for purpose that I've seen before include "Resolve; reason" , "Aim, intention, design" , "Goal, aim or intent" , "Reason for existence" , "Resolve, objective" .)