(nautical,dated) Any member of a ship'screw who is not required to keep the night-watch.[1]
A mechanical device such as apulley orwheel that does not transmitpower through its own axle, but forms part of a gear train, supports a moving belt, etc.[2][3]
1890,The Northwestern Miller, volume29, page563:
FOR SALE AT A BARGAIN.[…] Four run stones, Munson underrunners, 3 ft diameter.[…] All withidlers and in the best condition.
