/huy"peuh kawst', hip"euh-/ , n.
a hollow space or system of channels in the floor or walls of some ancient Roman buildings that provided a central heating system by receiving and distributing the heat from a furnace.
[ 1670-80; hypocaustum hypókauston room heated from below, equiv. to hypo- HYPO- + kaustón, neut. of kaustós (verbal adj.) heated, burned; see CAUSTIC ]