Definition of average:
"the average of 10, 20 and 24 is (10 + 20 + 24)/3 = 18."
(adj) :
constituting or relating to the average; neither very good nor very bad; rated somewhere in the middle of all others in the same category
"the average age of the participants was 18.5."
(v) :
to compute the arithmetic mean of; over a period of time or across members of a population, to have or generate a mean value of
"if you average 10, 20 and 24, you get 18."