A spindle or axle of a wheel.
A stimulus or driving force.
A bar or beam of wood or iron, connecting the opposite wheels of a carriage, on the ends of which the wheels revolve.
A rotating shaft that drives (or is driven by) a crank.
To deform in such a manner that part of the rod or bolt is displaced sideways, offset from the longitudinal axis of the part, but remains parallel with the part's main longitudinal axis, with the final shape somewhat resembling a crankshaft.