Meaning of TRANSMISSION in English
System in an engine that transmits power generated by the engine to the point where it is to be used.
Most mechanical transmissions function as rotary speed changers; the ratio of the output speed to the input speed may be either constant (as in a gearbox) or variable. On variable-speed transmissions, the speeds may be variable in individual steps (as on an automobile or some machine-tool drives) or continuously variable within a range. Step-variable transmissions, with some slip, usually use either gears or chains and provide fixed speed ratios with no slip; stepless transmissions use belts, chains, or rolling-contact bodies.
Britannica Concise Encyclopedia. Краткая энциклопедия Британика. 2012