cu·mu·lus | \ˈkyü-myə-ləs \
plural cumuli\ˈkyü-myə-ˌlī, -ˌlē \

Definition of cumulus 

2 [ New Latin, from Latin ] : a dense puffy cloud form having a flat base and rounded outlines often piled up like a mountain — see cloud illustration

Examples of cumulus in a Sentence

the cumulus of sundry things that fill up one's attic and somehow sum up a lifetime of experiences

Recent Examples on the Web

At sunset, a mix of alto cirrus with mare�s tails and cumulus provide a backdrop to pristine Forester Lake at 10, 240 feet, nestled in the Great Western Divide. Tom Stienstra, San Francisco Chronicle, "Nature’s fortune-tellers predicted wild weather for Memorial Day weekend," 28 May 2018 The air then lifts straight up, mixes with the moist layer, and creates the towering cumulus. Tom Stienstra, San Francisco Chronicle, "Mountain thunder, lightning mean summer has arrived," 21 May 2018 Forecast was almost perfect with 90% favorable weather outlook, only a slight concern that cumulus clouds might get really big. Paul Brinkmann,, "SpaceX set for second TESS launch attempt Wednesday evening," 18 Apr. 2018 Clouds come in all shapes and sizes: wispy, high cirrus, puffy cumulus, the low, gray stratocumulus layers that blanket gloomy days. Kate Marvel, Scientific American, "Will Changing Cloud Cover Accelerate Global Warming?," 8 Dec. 2017 Tufts of cumulus, floodlit from below, had been painted on the ceiling above the plane. Gideon Lewis-kraus, New York Times, "Selling Airborne Opulence to the Upper Upper Upper Class," 23 Jan. 2018 If one thermal peters out, head for the nearest cumulus cloud or dark field. Thermals can last 10 to 30 minutes or so. David Patterson, star-telegram, "A Soaring Passion," 27 Oct. 2017 The staging lights, the wheelies, the hateful cumulus of tire smoke enveloping the burnout box—to Boomers the Demon looks like Heaven. WSJ, "2018 Dodge Challenger SRT Demon: A Drag-Racing Beast, Unleashed," 20 July 2017 The day will start off sunny with afternoon cumulus clouds developing. Thomas Novelly, The Courier-Journal, "Could clouds block the once-in-a-lifetime eclipse in Kentucky?," 15 Aug. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'cumulus.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of cumulus

1659, in the meaning defined at sense 1

History and Etymology for cumulus


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Statistics for cumulus

Last Updated

16 Sep 2018

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The first known use of cumulus was in 1659

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English Language Learners Definition of cumulus

: a type of thick cloud that is rounded on top and has a flat base


cu·mu·lus | \ˈkyü-myə-ləs \
plural cumuli\-ˌlī, -ˌlē \

Kids Definition of cumulus

: a massive cloud form having a flat base and rounded outlines often piled up like a mountain


cu·mu·lus | \ˈkyü-myə-ləs \
plural cumuli\-ˌlī, -ˌlē \

Medical Definition of cumulus 

: the projecting mass of granulosa cells that bears the developing ovum in a graafian follicle

called also discus proligerus

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Comments on cumulus

What made you want to look up cumulus? Please tell us where you read or heard it (including the quote, if possible).


exaggeratedly or childishly emotional

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