Duct (industrial exhaust)
WordNet
noun
(1) An enclosed conduit for a fluid
(2) A bodily passage or tube lined with epithelial cells and conveying a secretion or other substance
"The tear duct was obstructed"
"The alimentary canal"
"Poison is released through a channel in the snake's fangs"
(3) A continuous tube formed by a row of elongated cells lacking intervening end walls