Rif"fle (?), n. [CF. G. riffeln, riefeln, to groove. Cf. Rifle a gun.] (Mining)
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.
© Webster 1913
Rif"fle (?), n. [Cf. Riffle a trough.]
A ripple in a stream or current of water; also, a place where the water ripples, as on a shallow rapid. [Local, U. S.]
The bass have left the cool depth beside the rock and are on the riffle or just below it.
James A. Henshall.
© Webster 1913