duct

(noun) a bodily passage or tube lined with epithelial cells and conveying a secretion or other substance. Synonyms: epithelial duct, canal, channel. Examples: "The tear duct was obstructed." "The alimentary canal." "Poison is released through a channel in the snake's fangs."

(noun) a continuous tube formed by a row of elongated cells lacking intervening end walls.

(noun) an enclosed conduit for a fluid.