Emily Dickinson Lexicon

SLUICE, or SLUSE, n. [D. sluis, a sluice, a lock; G. schleuse, a floodgate, and schloss, a lock, from schliessen, to shut; Sw. sluss; Dan. sluse; Fr. ecluse; It. chiusa, an inclosure. The Dutch sluiten, Dan. slutter, to shut, are the G. schliessen; all formed on the elements of Ld, Ls, the root of Eng. lid, L. claudo, clausi, clausus; Low L. exclusa. The most correct orthography is Sluse.]

1. The stream of water issuing through a flood-gate; or the gate itself. If the word had its origin in shutting, it denoted the frame of boards or planks which closes the opening of a mill dam; but I believe it is applied to the stream, the gate and channel. It is a common saying, that a rapid stream runs like a sluse.
2. An opening; a source of supply; that through which any thing flows. Each sluice of affluent fortune open'd soon. – Harte.