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 With a resolution of 3 micron and a field of view of around one millimeter, this lens, which is packaged in red, allows the user to see cells and microorganisms like protozoans and water bears. Courtney Linder, Popular Mechanics, "If You've Ever Wanted a Smartphone Microscope, Now's Your Chance," 22 Nov. 2019 The answer is Ginkgo Bioworks, a synthetic biology foundry that tinkers with the genes in microorganisms to produce new proteins, scents, antibiotics, cannabinoids, and other products. BostonGlobe.com, "Ginkgo, a Boston biotech venture, is a magnet for VC money - The Boston Globe," 20 Sep. 2019 For approximately every human cell in our bodies, there is a tiny microorganism living inside us. Jenna Sternberg, Smithsonian, "The Gut Microbiome Could Speed Up the Progression of Alzheimer’s Disease," 13 Sep. 2019 There are still lifes and landscapes, abstract and impressionist paintings, and a playful yet serious fiber art piece that pays homage to minute microorganisms that humans ignore at their peril. Denise Coffey, courant.com, "“New Perspectives” On Display At Spirol Gallery," 29 July 2019 Heating the soil should destroy microorganisms living in it, according to Straat. Mary Grace Keller, baltimoresun.com/maryland/carroll, "In search of life: Sykesville woman pens book on first NASA venture to land on Mars, 1976 Viking mission," 10 Nov. 2019 The limits to alien life may differ from those imposed on our own world’s microorganisms. Robin George Andrews, New York Times, "They Didn’t Find Life in a Hopeless Place," 1 Nov. 2019 During Wednesday’s outing, Kate will view some of the museum’s specimens and see DNA sequencing in action, done to identify the tiniest insects and microorganisms playing a part in the environment. Stephanie Petit, PEOPLE.com, "Kate Middleton Steps Out in the Perfect Fall Look (That Has a Connection to Meghan Markle!)," 9 Oct. 2019 Two of these components—one of which happens to be red when isolated and the other blue—killed staph and TB microorganisms, suggesting their potential as antibiotics. Rachel Crowell, Scientific American, "Scorpion Venom Could Lead to New Antibiotics," 4 Oct. 2019

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

30 Nov 2019

Cite this Entry

“Microorganism.” The Merriam-Webster.com Dictionary, Merriam-Webster Inc., https://www.merriam-webster.com/dictionary/microorganism. Accessed 7 December 2019.

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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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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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