from The Century Dictionary and Cyclopedia
- n. That part of the front axle of a motor-car which furnishes the bearing for front wheels. Each wheel fits upon one arm of a knuckle, the other being connected by links to the steering-wheel mechanism. The knuckle is supported in a strong yoke at the end of the axle proper, so that the vertical plane in which the wheels turn can be turned at any desired angle with the long axis of the vehicle and turn the latter in the desired direction. The wheels turn on the knuckle-arm by ball-bearings.
Sorry, no etymologies found.