| cumulonimbus | (n) a dark cloud of great vertical extent charged with electricity; associated with thunderstorms, Syn. thundercloud, cumulonimbus cloud |
| cumulous | (adj) thrown together in a pile, Example: a desk heaped with books; heaped-up ears of corn; ungraded papers piled high |
| Cumulose | a. [ From Cumulus. ] Full of heaps. [ 1913 Webster ] |
| Cumulostratus | n. (Meteor.) A form of cloud. See Cloud. [ 1913 Webster ] |