mi·​cro·​or·​gan·​ism | \ ˌmī-krō-ˈȯr-gə-ˌni-zəm How to pronounce microorganism (audio) \

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 In their motion to dismiss, attorneys also pointed to microorganism and pollution exclusions in the contracts. Michael Braga, USA TODAY, "Minor league baseball teams the latest to sue insurance companies for failing to pay business interruption insurance," 9 July 2020 At its core, hydroxychloroquine, along with its close cousin chloroquine, is an antimalarial medication that primarily treats and prevents the mosquito-borne infection by killing the microorganism (a plasmodium parasite) that causes it. Popular Science, "Hydroxychloroquine isn’t the miracle COVID-19 treatment many hoped it would be," 29 May 2020 Sharpe has begun lending his stock of hydroxyl generators, which use ultraviolet light to kill microorganisms in the air, to local hospitals and homes for the elderly, where many are particularly vulnerable to COVID-19, the coronavirus disease. Chase Difeliciantonio, SFChronicle.com, "Workplace cleanliness a critical issue for businesses still operating in coronavirus era," 28 Mar. 2020 Growth is stopped when food is frozen, but microorganisms are not destroyed. Washington Post, "The big chill: A guide to using your freezer," 13 May 2020 Composting beds instead rely on naturally-occurring aerobic microorganisms that live in the moisture surrounding the organic matter and break down food scraps into heat, water and carbon dioxide. Beth Gardiner, New York Times, "That Compost Bin in the Living Room," 6 May 2020 The research, published in the journal Nature, is the product of screening 100,000 microorganisms. Nusmila Lohani, The Christian Science Monitor, "Points of Progress: Breakthrough in plastic recycling, and more," 1 May 2020 Such a reshuffling of species around the planet could mean that animals that host unique disease-causing microorganisms will live side by side with those that would not normally host them, creating new transmission pathways. Sara Goudarzi, Scientific American, "How a Warming Climate Could Affect the Spread of Diseases Similar to COVID-19," 29 Apr. 2020 Most of these contain probiotics—live microorganisms that, when consumed in adequate amounts, have a health benefit to the dog. The Editors, Field & Stream, "Supplements to Keep Your Dog Healthy," 24 Apr. 2020

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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Time Traveler for microorganism

Time Traveler

The first known use of microorganism was in 1880

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Statistics for microorganism

Last Updated

22 Jul 2020

Cite this Entry

“Microorganism.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/microorganism. Accessed 8 Aug. 2020.

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How to pronounce microorganism (audio)

English Language Learners Definition of microorganism

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


mi·​cro·​or·​gan·​ism | \ ˌmī-krō-ˈȯr-gə-ˌni-zəm How to pronounce microorganism (audio) \

Kids Definition of microorganism

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


mi·​cro·​or·​gan·​ism | \ -ˈȯr-gə-ˌniz-əm How to pronounce microorganism (audio) \

Medical Definition of microorganism

: an organism of microscopic or ultramicroscopic size

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Spanish Central: Translation of microorganism

Nglish: Translation of microorganism for Spanish Speakers

Britannica.com: Encyclopedia article about microorganism

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