a bulbous, domelike roof ending in a sharp point, characteristically used in Russian Orthodox church architecture to cover cupolas or towers.
Origin of onion dome
First recorded in 1955–60
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
a bulb-shaped dome characteristic of Byzantine and Russian church architecture
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012