CUMULUS
pile, heap, mound, agglomerate, cumulation, cumulus
(noun) a collection of objects laid on top of each other
cumulus, cumulus cloud
(noun) a globular cloud
Source: WordNet® 3.1
Etymology
Noun
cumulus (plural cumuli)
A large white puffy cloud that develops through convection. On a hot, humid day, they can form towers and even become cumulonimbus clouds.
A mound or heap.
Source: Wiktionary
Cu"mu*lus (k"m-ls), n.; pl. Cumuli (-l. Etym: [L., a heap. See
Cumber.] (Meteor.)
Definition: One of the four principal forms of clouds. SeeCloud.
Source: Webster’s Unabridged Dictionary 1913 Edition