noun
: a key for securing a member to a machine shaft that fits into a keyway in the secured member and is concave to grip the shaft by friction — compare flat key , sunk key
noun
: a key for securing a member to a machine shaft that fits into a keyway in the secured member and is concave to grip the shaft by friction — compare flat key , sunk key
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012