differential

(noun) the result of mathematical differentiation; the instantaneous change of one quantity relative to another; df(x)/dx. Synonyms: derived function, derivative, differential coefficient, first derivative.

(noun) a quality that differentiates between similar things.

(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. Synonyms: differential gear.

(adj) relating to or showing a difference. Example: "Differential treatment."

(adj) involving or containing one or more derivatives. Example: "Differential equation."