A device for producing straight-line motion from circular motion, on the principle that a pin fastened in the periphery of a gear wheel will describe a straight line when the wheel rolls around inside a fixed internal gear of twice its diameter.

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.

prayer wheel

(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.

(horology) The wheel of an escapement.

(engineering) A form of cam shaped like a heart, used to convert uniform rotary motion into uniform reciprocating motion.

Ferris wheel

A stitch resembling a spider's web, worked into the material, and not over an open space.