An "onion dome" is a type of architectural dome that is characterized by its bulbous, rounded shape, resembling the layers of an onion. This design is often seen in Russian and Eastern Orthodox churches, where it serves both aesthetic and symbolic purposes. The dome typically tapers to a point at the top, creating a distinctive silhouette. Onion domes are usually painted in bright colors, such as gold or green, and are often adorned with decorative elements like crosses. They are designed to be visually striking, drawing attention to the building and enhancing its spiritual significance. Examples can be found in famous structures like the Saint Basil's Cathedral in Moscow.