sluice

An artificial passage for water, fitted with a valve or gate, for example in a canal lock or a mill stream, for stopping or regulating the flow.

A water gate or floodgate.

Hence, an opening or channel through which anything flows; a source of supply.

The stream flowing through a floodgate.

A long box or trough through which water flows, used for washing auriferous earth.

An instance of wh-stranding ellipsis, or sluicing.

To emit by, or as by, flood gates.

To wet copiously, as by opening a sluice

“to sluice meadows”

To wash with, or in, a stream of water running through a sluice.

(more generally) To wash (down or out).

To flow, pour.

To elide the C` in a coordinated wh-question. See sluicing.