P / praefurnĭum
noun

praefurnĭum

gen. praefurni · gender neuter · decl. 2nd
prae-furnus.
The opening of a furnace; the door
The opening of a furnace, the door by which fuel is admitted: si uno praefurnio coques, Cato, R. R. 38, 1.—
The heating-room
The heating-room, or hot anteroom of a bath, = προπνιγεῖον, Vitr. 5, 10, 2; 7, 10.