an artificial waterway for navigation, irrigation, etc.

a long narrow arm of the sea penetrating far inland.

a tubular passage or cavity for food, air, etc., esp. in an animal or plant; a duct.

channel; watercourse.

Astronomy . one of the long, narrow, dark lines on the surface of the planet Mars, as seen telescopically from the earth.

to make a canal through.

noun

aqueduct , bottleneck , channel , choke point , conduit , course , cove , ditch , duct , estuary , firth , trench , water , watercourse , drain , erie , panama , strait , towpath , tube