(1):

(n.) A furnace for melting iron or other metals in large quantity, - used chiefly in foundries and steel works.

(2):

(n.) A revolving shot-proof turret for heavy ordnance.

(3):

(n.) 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.

(4):

(n.) The top of the spire of the cochlea of the ear.

(5):

(n.) A small structure standing on the top of a dome; a lantern.