Wheel-and-axle meaning

A larger wheel or pulley that is fixed to a shaft, a smaller wheel or pulley, or a drum, to increase mechanical advantage or speed: the wheels are often grooved and operated like pulleys.

A simple machine consisting of an axle to which a wheel is fastened so that torque applied to the wheel winds a rope or chain onto the axle, yielding a mechanical advantage equal to the ratio of the diameter of the wheel to that of the axle.