An open channel or trough used to direct or divert liquids.
A ravine or gorge, usually one with water running through.
To transport (logs of wood) by floating them along a water-filled channel or trough.
Any small aperture or vent for air or other fluid.
A pore or opening used (especially by arthropods and some fish) for respiration.
The blowhole of a whale, dolphin or other similar species.