sluice n.

c. 1400, earlier scluse (mid-14c.), "dam with a water-gate," a shortening of Old French escluse "sluice, floodgate" (Modern French écluse), from Late Latin exclusa "barrier to shut out water" (in aqua exclusa "water shut out," i.e. separated from the river), from fem. singular of Latin exclusus, past participle of excludere "to shut out" (see exclude).

The meaning "gate or contrivance by which the flow of water is controlled" is from 1610s. In mining, "trough made of boards for separating gold from gravel and sand," 1851. Sluiceway "channel or waterway fed by a sluice" is by 1779.

1590s, "let out, cause to flow out; draw off (liquid)," by or as by a sluice, from sluice (n.). In gold-mining, "to scour or cleanse by a sluice," by 1859. Related: Sluiced; sluicing.