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 Cells are equipped with multiple alarms that signal the presence of an invading microorganism or inappropriate cell damage. William A. Haseltine, Forbes, 21 Apr. 2022 However, the company had not identified the microorganism that might have contaminated the potatoes at the time of the recall announcement. Chris Smith, BGR, 12 July 2022 Bed bugs have been suspected in the transmission of more than 40 disease organisms, but there is little evidence bed bugs transmit human pathogens, with the possible exception of the microorganism that causes Chagas disease. Jerome Goddard, The Conversation, 3 June 2022 This supplement includes Lactobacillus acidophilus, a beneficial microorganism that aids in digestion. The Salt Lake Tribune, 13 June 2022 When the microorganism is detected, product recalls follow. Chris Smith, BGR, 29 May 2022 The microorganism can be found in all sorts of food products, including snacks. Chris Smith, BGR, 29 Apr. 2022 Both disinfect by oxidizing the cell membrane of microorganism, a process by which their molecules receive electrons from those membranes. Wes Siler, Outside Online, 28 Apr. 2020 Its product is derived from mycelium, the fungal microorganism that makes up mushrooms. Justin Ray, Los Angeles Times, 7 Mar. 2022 See More

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.

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

4 Aug 2022

Cite this Entry

“Microorganism.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/microorganism. Accessed 14 Aug. 2022.

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More Definitions for microorganism


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

More from Merriam-Webster on microorganism

Nglish: Translation of microorganism for Spanish Speakers

Britannica.com: Encyclopedia article about microorganism


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