Ancient Roman Heating System From Furnaces

This page is the CodyCross answer for the clue below from Making a Documentary, Group 1520, Puzzle 2 (Audience Reception).

Question is: Ancient Roman Heating System From Furnaces

and the answer is: HYPOCAUST

Word Meaning:

HYPOCAUST — An underfloor space or flue through which heat from a furnace passes to heat the floor of a room or a bath.

Definitions from Wiktionary.

Ancient Roman Heating System From Furnaces - Making a Documentary CodyCross Answers | CodyCross Solutions