Aspidosperma excelsum, a tree native to Peru. / Trochodendron aralioides, a tree or large shrub native to Japan, Taiwan, and southern Korea.

A pinion with cylindrical staves, instead of teeth, inserted at their ends in two parallel disks or plates.

In water-powered mills, a horizontal water wheel used to power a grinding stone set in a tub; usually in the form of a short cylinder turned by the impact of one or more streams of water striking against vanes attached radially to the wheel.

A type of hubcap or inner wheel ornament that spins independently inside of a wheel itself when the vehicle is in motion, and continues to spin once the vehicle has come to a stop.

(engineering) One of a set of wheels of different sizes and number of teeth, that may be changed or substituted for one another in machinery, to produce a different but definite rate of angular velocity in an axis, as in cutting screws, gear, etc.

A noria.

Ferris wheel

A wheel whose rim and hub are connected by a continuous plate of metal, instead of by arms or spokes.

A circular window having radiating mullions arranged like the spokes of a wheel.

hamster wheel