Wordnet 3.0
NOUN (1)
1. 
 a bodily passage or tube lined with epithelial cells and conveying a secretion or other substance; 
- Example: "the tear duct was obstructed"- Example: "the alimentary canal"- Example: "poison is released through a channel in the snake's fangs"[syn: duct, epithelial duct, canal, channel]
WordNet (r) 3.0 (2006):
epithelial duct
    n 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" [syn:
         duct, epithelial duct, canal, channel]