room with a sunken hearth
A traditional Japanese room featuring an irori (sunken hearth), often used for cooking and heating in old farmhouses.
Old private houses sometimes still have a room with a sunken hearth.
Compound of 焚火 (takibi, 'open fire') + の (possessive particle) + 間 (ma, 'room'). The exact historical derivation is uncertain, but the term describes a room centered around a fire.