Axle (noun)

A shaft or spindle on which a wheel rotates.

Origin:

Late middle english (denoting a pin or spindle): from old norse axill; the sense "spindle carrying a wheel" (early 16th century) is probably a separate word.

Examples:

1. The axle of a cart is what the wheels turn around.
2. A bicycle has two axles, one for the front wheel and one for the rear wheel.
3. The axle of a car transfers power from the engine to the wheels.
4. The axle of a trailer helps to distribute the weight of the load being transported.
5. The axle of a locomotive helps to carry the weight of the train.