Any sea urchin of the genus Rotula having a round, flat shell; a type of sand dollar.

A variety of bournonite with wheel-shaped twin crystals.

Alternative form of wheelhorse.

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.

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

hamster wheel

A press by which railway-car wheels are forced on, or off, their axles.

(US) Any assassin bug of the genus Arilus, large true bugs with wheel-shaped pronotal armor. They are predators upon soft-bodied insects.

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