|an ancient Roman heating system in which hot air circulated under the floor and between double walls|
|[C17: from Latin hypocaustum, from Greek hupokauston room heated from below, from hupokaiein to light a fire beneath, from |
in building construction, open space below a floor that is heated by gases from a fire or furnace below and that allows the passage of hot air to heat the room above. This type of heating was developed by the Romans, who used it not only in the warm and hot rooms of the baths but also almost universally in private houses in the northern provinces.
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