microorganism

noun
mi·​cro·​or·​gan·​ism | \-ˈȯr-gə-ˌni-zəm \

Definition of microorganism 

: an organism (such as a bacterium or protozoan) of microscopic or ultramicroscopic size

Examples of microorganism in a Sentence

Recent Examples on the Web

Only now, with the background knowledge that (a) bacteria make a lot of bioactive compounds, many of which do combat other microorganisms, and that (b) phages are a major scourge for bacteria, did researchers think to check. Diana Gitig, Ars Technica, "Bacteria engage in chemical warfare against viruses," 5 Dec. 2018 The whole category is based on a molecule called beta-lactam, which is naturally secreted by the Penicillium chrysogenum fungus, giving the species a competitive advantage against other microorganisms in the wild. Jonathon Keats, Discover Magazine, "Bacteria That Eat Drugs Could Help Solve the Antibiotic Resistance Crisis," 8 Nov. 2018 This new protein family is even found in bacteria and other microorganisms that were never known to sense light until now. Shandria Sutton, Science | AAAS, "New ‘light-eating’ protein discovered in the Sea of Galilee," 5 July 2018 The cause is unknown, but earlier studies conclude that the skin microbiome -- the community of all the bacteria and other microorganisms living on the surface of the skin -- plays a major role. Ian Myles, CNN, "A possible new weapon against eczema: live bacteria," 17 May 2018 The immune system is notoriously complex, and Mr. Kinch offers a masterly exposition of the evolution and operation of our defense against what scientists call non-self, including disease-causing microorganisms. William F. Bynum, WSJ, "‘Between Hope and Fear’ Review: Anxieties Immune to Reason," 16 Aug. 2018 Using sunlight, plants and microorganisms take in carbon dioxide and emit oxygen. Umair Irfan, Vox, "Sucking CO2 out of the atmosphere, explained," 24 Oct. 2018 In Castine Harbor, Castine Kayak Adventures runs paddle trips on weekends for stargazing and spotting glow-in-the-dark aquatic microorganisms. Megan Michelson, Outside Online, "These Are the Best Stargazing Spots in North America," 13 July 2018 There is also the risk, however rare, of Acanthamoeba Keratitis (or AK), a type of eye infection caused by a microorganism found in some tap water and swimming pools. Katie Heaney, The Cut, "Are My Contacts Going to Make Me Go Blind?," 11 July 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'microorganism.' 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 microorganism

1880, in the meaning defined above

History and Etymology for microorganism

International Scientific Vocabulary

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Last Updated

14 Dec 2018

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Time Traveler for microorganism

The first known use of microorganism was in 1880

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More Definitions for microorganism

microorganism

noun

English Language Learners Definition of microorganism

biology : an extremely small living thing that can only be seen with a microscope

microorganism

noun
mi·​cro·​or·​gan·​ism | \ˌmī-krō-ˈȯr-gə-ˌni-zəm \

Kids Definition of microorganism

: a living thing (as a bacterium) that can only be seen with a microscope

microorganism

noun
mi·​cro·​or·​gan·​ism | \-ˈȯr-gə-ˌniz-əm \

Medical Definition of microorganism 

: an organism of microscopic or ultramicroscopic size

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More from Merriam-Webster on microorganism

Spanish Central: Translation of microorganism

Nglish: Translation of microorganism for Spanish Speakers

Britannica.com: Encyclopedia article about microorganism

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