duct

n. conduit, canal, passage, pipe (for conducting liquids or air)

A duct may refer to:Duct (HVAC) (Heating Ventilating and Air-Conditioning), for transfer of air between spaces in a buildingDuct (anatomy), various ducts in anatomy and physiologyDucted fan, motor for aircraftDuct tapeTelecommunicationAtmospheric ductA conduit which may be buried or encased
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Duct a passage with well-defined walls, especially a tubular structure for the passage of excretions or secretions. [more]Duct - Community and Resources

Noun
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"
(synonym) epithelial duct, canal, channel
(hypernym) passage, passageway
(hyponym) pore
(part-meronym) ampulla
2. a continuous tube formed by a row of elongated cells lacking intervening end walls
(hypernym) plant part, plant structure
(hyponym) laticifer
(part-holonym) vascular plant, tracheophyte
3. an enclosed conduit for a fluid
(hypernym) conduit
(hyponym) air-intake

(n.)
One of the vessels of an animal body by which the products of glandular secretion are conveyed to their destination.
  

(n.)
Guidance; direction.
  

(n.)
Any tube or canal by which a fluid or other substance is conducted or conveyed.
  

(n.)
A large, elongated cell, either round or prismatic, usually found associated with woody fiber.