differential

The differential gear in an automobile, etc.

A qualitative or quantitative difference between similar or comparable things.

(mathematics) An infinitesimal change in a variable, or the result of differentiation.

One of two coils of conducting wire so related to one another or to a magnet or armature common to both, that one coil produces polar action contrary to that of the other.

A form of conductor used for dividing and distributing the current to a series of electric lamps so as to maintain equal action in all.