(n.) A bar, pin or wedge, to secure a crank, pulley, coupling, etc., upon a shaft, and prevent relative turning; sometimes holding by friction alone, but more frequently by its resistance to shearing, being usually embedded partly in the shaft and partly in the crank, pulley, etc.
KEY (11)
Meaning of KEY (11) in English
Webster's English dictionary. Английский словарь Webster. 2012