·noun Any channel, receptacle, or depression, of a long and narrow shape; as, trough between two ridges, ·etc.
II. Trough ·add. ·noun The transverse section of a cyclonic area where the barometric pressure, neither rising nor falling, has reached its lowest point.
III. Trough ·noun 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.