Riffle



ENGLISH MEANING
noun
1.
A trough or sluice having cleats, grooves, or steps across the bottom for holding quicksilver and catching particles of gold when auriferous earth is washed; also, one of the cleats, grooves, or steps in such a trough. Also called ripple.
2.
A ripple in a stream or current of water; also, a place where the water ripples, as on a shallow rapid.