Lewis & Short

furnus (fornus, Varr. ap. Non. 531, 32), i, m. [Sanscr. ghar-, to lighten; cf.: fornus, fornax, and v. formus], an oven (syn.: caminus, fornax, clibanus): in furnum calidum condito, Plaut. Cas. 2, 5, 1: malim istius modi mi amicos furno mersos quam foro, id. Ep. 1, 2, 16; Varr. l. l.; Plin. 13, 4, 9, § 48; 19, 1, 3, § 18; 20, 9, 39, § 99; Ov. F. 6, 313. Used by the Romans as a warming-place, Hor. S. 1, 4, 36; id. Ep. 1, 11, 13.