The Collaborative International Dictionary
Caliduct
Caliduct \Cal"i*duct\, n. [See Caloriduct.] A pipe or duct used to convey hot air or steam.
Subterranean caliducts have been introduced.
--Evelyn.
Wiktionary
caliduct
n. A pipe or duct used, especially in ancient times, to convey hot air or steam for heating purposes.
Wikipedia
Caliduct
Caliducts were a kind of pipes, or canals, placed along the walls of houses and apartments, used by the ancients for the conveyance of heat to several remote parts of the house, from one common furnace.
Category:Heating, ventilating, and air conditioning