mid-15c., "heated room, bath-room," from Middle Low German or Middle Dutch stove, both meaning "heated room," which was the original sense in English; a general West Germanic word (Old English stofa "bath-room," Old High German stuba, German Stube "sitting room").
Of uncertain relationship to similar words in Romance languages (Italian stufa, French étuve "sweating-room;" see stew (v.)). One theory traces them all to Vulgar Latin *extufare "take a steam bath." The meaning "device for heating or cooking" is first recorded 1610s.