long and narrow strip of water made for boats or for irrigation | any small opening in the skin or outer surface of an animal |
a bodily passage or tube lined with epithelial cells and conveying a secretion or other substance | a minute epidermal pore in a leaf or stem through which gases and water vapor can pass |
(astronomy) an indistinct surface feature of Mars once thought to be a system of channels; they are now believed to be an optical illusion | any tiny hole admitting passage of a liquid (fluid or gas) |