cupola

Cupola comes from Italian cupola, from Latin cūpula (small cup, little barrel), the diminutive of cūpa (tub, barrel). The word names a dome — specifically a small dome crowning a roof or turret. A cup turned upside down over a building.

The Romans built the greatest dome of antiquity — the Pantheon — but they called it tholus, not cupola. It was Italian Renaissance architects who revived dome-building and gave it its modern name. Brunelleschi's dome in Florence (1436) was the breakthrough, though it's technically called a duomo (cathedral).

English borrowed 'cupola' in the 1540s, initially for Italian architecture, then generalizing to any small dome. The word traveled to colonial America, where cupolas crowned courthouses, churches, and barns from Maine to Virginia. A cupola was how you recognized the most important building in town.

In military usage, a cupola is the armored rotating turret on a tank — the commander's dome. The same word names the observation module on the International Space Station. From Renaissance rooftops to outer space, the little cup endures.