Trough :: Trough (n.) 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..
Trough :: Trough (n.) Any channel, receptacle, or depression, of a long and narrow shape; as, trough between two ridges, etc..
Trough-shell :: Trough-shell (n.) Any bivalve shell of the genus Mactra. See Mactra.