From Longman Dictionary of Contemporary Englishthundercloudthun‧der‧cloud /ˈθʌndəklaʊd $ -ər-/ noun [countable] HEMa large dark cloud that you see before or during a storm
Examples from the Corpus
thundercloud• We sneaked over once and were well into a doubleheader when our grandmother saw us and swooped in like a thundercloud.• The monster was a distant thundercloud that boiled higher and higher on the horizon.• Much water is transported this way over a summer, bypassing the monopoly thunderclouds have on water delivery elsewhere.• He thought he heard Zeus and Hera quarrelling among the thunderclouds.• She looks up at the thunderclouds.• The early evening had been fine and then it darkened over with thundercloud and got warmer. 