Old English ofen "furnace, oven," from Proto-Germanic *ukhnaz (cognates: Old Frisian, Dutch oven, Old High German ovan, German Ofen, Old Norse ofn, Old Swedish oghn, Gothic auhns), from PIE *aukw- "cooking pot" (cognates: Sanskrit ukhah "pot, cooking pot," Latin aulla "pot," Greek ipnos), originally, perhaps, "something hollowed out." The oven-bird (1825) so called because of the shape of its nest. In slang, of a woman, to have (something) in the oven "to be pregnant" is attested from 1962.