cumulus
nounUK /ˈkjuːmjʊləs/ · US /ˈkjumjələs/
Etymology Learned borrowing from Latin cumulus. Doublet of comble. Sense 2 (“type of cloud”) was coined by the British chemist and amateur meteorologist Luke Howard (1772–1864): see the 1803 quotation.
1
A heap or mound.
2
Climatology, Meteorology, Natural sciences A large white, puffy cloud that develops through convection.
- [page 99] Cumulus. […] Convex or conical heaps, increasing upward from a horizontal base. […] [page 101] The cumulus of fair weather has a moderate elevation and extent, and a well defined rounded surface. Previous to rain it increases more rapidly, appears lower in the atmosphere, and with its surface full of loose fleeces or protuberances.1803 July, Luke Howard, “XVIII. On the Modifications of Clouds, and on the Principles of Their Production, Suspension, and Destruction; being the Substance of an Essay Read before the Askesian Society in the Session 1802–3.”, in Alexander Tilloch, editor, The Philosophical Magazine and Journal: Comprehending the Various Branches of Science, the Liberal and Fine Arts, Agriculture, Manufactures, and Commerce, volume XVI, number 62, London: […] [Richard Taylor] for Alexander Tilloch; and sold by Messrs. Richardson, […], →ISSN, →OCLC, pages 99 and 101:
- In the sketch (which is taken about 75 Jovian days after that of the 2nd July) there is shown a dark copper-coloured streak along the southern margin of the south brown belt, butting on to a bluff-headed streak of cumulus cloud which may be the same remarkable bluff head noticed on July 2.1878 November 8, C. Todd, “Observations at the Adelaide Observatory”, in Monthly Notices of the Royal Astronomical Society, volume 39, number 1, page 18:
2 more examples
- There were some new cumuli in the east, out above the water, and they began to take the late afternoon sun.1919, Henry B[lake] Fuller, “Cope Enlivens the Country”, in Bertram Cope’s Year: A Novel, Chicago, Ill.: Ralph Fletcher Seymour, The Alderbrink Press, →OCLC, page 102:
- 2007 September 1, "Who’s afraid of Google?: The world’s internet superpower faces testing times", in The Economist, The Economist Newspaper Ltd, ISSN 0013-0613, volume 384, number 8544, page 9, Ironically, there is something rather cloudlike about the multiple complaints surrounding Google. The issues are best parted into two cumuli: a set of “public” arguments about how to regulate Google; and a set of “private” ones for Google’s managers, to do with the strategy the firm needs to get through the coming storm.
- Derived terms
- cumulus oophorus, fumulus, pyrocumulus, roll cumulus, stratocumulus