CUPOLA

noun Etymology: Italian, from Latin cupula, diminutive of cupa tub Date: 1549 1. a rounded vault resting on a usually circular base and forming a roof or a ceiling, a small structure built on top of a roof, a vertical cylindrical furnace for melting iron in the foundry that has tuyeres and tapping spouts near the bottom, a raised observation post in the roof of a railroad caboose, ~ed adjective