Originally Mining (chiefly in gold-washing). Any of various contrivances or devices (such as grooves, bars, or slats) on the bottom of a sluice or…

A device for restricting the flow of a gas or fluid, e.g. by means of a valve, narrowed orifice, use of a porous medium, etc. Frequently attributive.

A plate hindering or regulating the passage of fluid through an outlet or inlet, or the direction of sound.

Originally and chiefly Mining. The action of sorting a stream of particles using a system of riffles. Also: the system of riffles itself (riffle, n.…