An Etymological Dictionary of the German Language/Stube
Stube, f., ‘room, chamber,’ from MidHG. stube, OHG. stuba, f., ‘room with means for heating, sitting-room, bathroom’; common to OTeut.; comp. Du. stoof, ‘foot-stove, drying-room,’ AS. stofa, E. stove, OIc. stofa, ‘room, bathroom with a stove.’ Although the Romance origin of the cognates is impossible (Ital. stufa, Fr. étuve, ‘sweating-room, stove,’ are certainly borrowed from Teut.), this does not prove that the words are genuinely Teut. The word stuba was adopted in Finn. as tupa, in Lith. as stubà; comp. OSlov. istŭba, izba, Hung. szoba, Turk. soba, ‘room.’ The primary meaning of the Teut. word is ‘heated room,’ as may be inferred from Du. stoven, ‘to stew, warm up’ (whence Ital. stufare, Fr. etuver, ‘to foment’).