cumulonimbus

Definition

A cloud with a tall structure and flat base, often associated with thunderstorms.

Etymology

From Latin cumulus (“heap”) + nimbus (“cloud”).

Example Sentences

• "The one to the east (which at the moment seemed to be leaping straight out of the heart of a sinister slaty-purple patch of cumulonimbus) drained the Lake of the Hanging Glaciers; that to the west a desolate rock and ice-walled valley which was rimmed by some of the highest summits in the Selkirks."