Definition of "Differential" :

noun: a bevel gear that permits rotation of two shafts at different speeds; used on the rear axle of automobiles to allow wheels to rotate at different speeds on curves

noun: a quality that differentiates between similar things

noun: the result of mathematical differentiation; the instantaneous change of one quantity relative to another; df(x)/dx

adjective: relating to or showing a difference

"Differential treatment."

adjective: involving or containing one or more derivatives

"Differential equation."