a roof having a rounded form, hemispherical or nearly so; also, a ceiling having the same form. when on a large scale it is usually called dome.-a small structure standing on the top of a dome; a lantern.-a furnace for melting iron or other metals in large quantity, -- used chiefly in foundries and steel works.-a revolving shot-proof turret for heavy ordnance.-the top of the spire of the cochlea of the ear.