1.A pipe or duct used to convey hot air or steam.Subterranean caliducts have been introduced.- Evelyn.
caliduct
enUK
caliduct
1. A duct or pipe for conveying hot air, hot water, or steam for heating. 2. In the ancient Roman systems of furnace heating, a hot-air flue, usually of terra-cotta or built up with brick partitions and tile facings.