'Thundercloud' definitions:

Definition of 'thundercloud'

From: WordNet
noun
A dark cloud of great vertical extent charged with electricity; associated with thunderstorms [syn: cumulonimbus, cumulonimbus cloud, thundercloud]

Definition of 'Thundercloud'

From: GCIDE
  • Thundercloud \Thun"der*cloud`\, n. A cloud charged with electricity, and producing lightning and thunder. [1913 Webster]

Synonyms of 'thundercloud'

From: Moby Thesaurus