duct in WordNet English dictionary

1. 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"
   duct  epithelial duct  canal  channel 
   
2. an enclosed conduit for a fluid
   duct 
   
3. a continuous tube formed by a row of elongated cells lacking intervening end walls
   duct