means The act of sending something from one place or person to another, or the mechanical assembly in a vehicle that transfers power from the engine to the wheels.

from From Latin transmittere, 'to send across' — built from trans- ('across') and mittere ('to send'), the same restless verb that gave us 'missile,' 'mission,' and 'message.' For centuries it simply meant passing something along: property, signals, disease. The car-part sense is a young upstart, arriving with the automobile age to name the gearbox that 'sends across' the engine's power to the wheels.