Noun: cumulonimbus (cumulonimbi) ,kyoo-myu-low'nim-bus
- A dark cloud of great vertical extent charged with electricity; associated with thunderstorms
"The cumulonimbus cloud loomed ominously, signaling an approaching storm";
- cumulonimbus cloud, thundercloud
Derived forms: cumulonimbi
Type of: cloud
Encyclopedia: Cumulonimbus