TROUGH

A long, hollow vessel, generally for holding water or other liquid, especially one formed by excavating a log longitudinally on one side; a long tray; also, a wooden channel for conveying water, as to a mill wheel.

Any channel, receptacle, or depression, of a long and narrow shape; as, trough between two ridges, etc. Trough gutter (Arch.), a rectangular or V-shaped gutter, usually hung below the eaves of a house. -- Trough of the sea, the depression between two waves.