Wiktionary
cumulonimbi
n. (plural of cumulonimbus English)
WordNet
cumulonimbi
See cumulonimbus
cumulonimbus
n. a dark cloud of great vertical extent charged with electricity; associated with thunderstorms [syn: cumulonimbus cloud, thundercloud]
[also: cumulonimbi (pl)]
Usage examples of "cumulonimbi".
Purple-gray cumulonimbi were piling up to great heights, crowding in from the west, borne on the back of a keen salt wind.