a bulb-shaped dome characteristic of Byzantine and Russian church architecture
onion dome in American English
noun
Architecture
a bulbous, domelike roof ending in a sharp point, characteristically used in Russian Orthodox church architecture to cover cupolas or towers
Word origin
[1955–60]This word is first recorded in the period 1955–60. Other words that entered Englishat around the same time include: geodesic dome, life-support, opioid, rollout, software