n.
Function: noun
Etymology: perhaps alteration of ruffle
Date: 1785
1 a : a shallow extending across a streambed and causing broken water b : a stretch of water flowing over a riffle
2 : a small wave or succession of small waves : RIPPLE
3 a : any of various contrivances (as blocks or rails) laid on the bottom of a sluice or launder to make a series of grooves or interstices to catch and retain a mineral (as gold) b : a groove or interstice so formed
4 : a cleat or bar fastened to an inclined surface in a gold-washing apparatus to catch and hold mineral grains
5 [ 1 riffle ] a : the act or process of shuffling (as cards) b : the sound made while doing this