noun

1. an artificial waterway for transportation or irrigation
2. a river artificially improved by locks, levees, etc. to permit navigation
3. any of the long, narrow lines, visible from earth, on the planet Mars: once thought by some to be canals but now known to be optical illusions
4. Anat. any of various tubular passages or ducts

Etymology: ME, pipe or tube < OFr < L canalis, pipe, groove, channel < canna, reed: see cane

transitive verb canalled -·nalled′ or canaled -·naled′, canalling -·nal′·ling or canaling -·nal′·ing