n. 1 an artificial waterway for inland navigation or irrigation. 2 any of various tubular ducts in a plant or animal, for carrying food, liquid, or air. 3 Astron. any of a network of apparent linear markings on the planet Mars, which are observed from earth but not at close range. canal boat a long narrow boat for use on canals. canal ray a beam of positive ions moving through a bored hole in the cathode of a high-vacuum tube.
[ ME f. OF (earlier chanel) f. L canalis or It. canale ]