function (n)
purpose (n)
role (n)
use (n)

Definition: what something is used for
Example: the function of an auger is to bore holes. ballet is beautiful but what use is it?.

employment (n)
exercise (n)
usage (n)
use (n)
utilisation (n)
utilization (n)

Definition: the act of using
Example: he warned against the use of narcotic drugs. skilled in the utilization of computers.

exploitation (n)
using (n)
victimisation (n)
victimization (n)

Definition: an act that exploits or victimizes someone (treats them unfairly)
Example: capitalistic exploitation of the working class. paying Blacks less and charging them more is a form of victimization.