microorganism
noun
mi·cro·or·gan·ism
ˌmī-krō-ˈȯr-gə-ˌni-zəm 
: an organism (such as a bacterium or protozoan) of microscopic or ultramicroscopic size
Examples of microorganism in a Sentence
Recent Examples on the Web
Plastics, microplastics and toxic chemicals can hurt and kill the microorganisms that make his compost healthy and valued.
—
Los Angeles Times, 4 July 2025
The gut microbiota is the set of microorganisms that live in our intestines, performing a number of actions that have a direct impact on skin tissue.
—Violeta Valdés, Vogue, 2 July 2025
The vitality of the microorganisms present determines the ultimate success of the pile, and an overly acidic environment can disrupt their activity.
—Anthony Reardon, Kansas City Star, 27 June 2025
In the last several years, researchers have discovered that living beings contribute more to Earth’s clouds than expected thanks to gases from plants and plankton, and sea spray that propels microorganisms and proteins skyward.
—Max G. Levy, Smithsonian Magazine, 26 June 2025
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Los Angeles Times, 4 July 2025
The gut microbiota is the set of microorganisms that live in our intestines, performing a number of actions that have a direct impact on skin tissue.
—Violeta Valdés, Vogue, 2 July 2025
The vitality of the microorganisms present determines the ultimate success of the pile, and an overly acidic environment can disrupt their activity.
—Anthony Reardon, Kansas City Star, 27 June 2025
In the last several years, researchers have discovered that living beings contribute more to Earth’s clouds than expected thanks to gases from plants and plankton, and sea spray that propels microorganisms and proteins skyward.
—Max G. Levy, Smithsonian Magazine, 26 June 2025
See All Example Sentences for microorganism
Cite this Entry
“Microorganism.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/microorganism. Accessed 18 Jul. 2025.
Copy CitationKids Definition
microorganism
noun
mi·cro·or·gan·ism
ˌmī-krō-ˈȯr-gə-ˌniz-əm
: an organism (as a bacterium) of microscopic or less than microscopic size
Medical Definition
microorganism
noun
mi·cro·or·gan·ism
-ˈȯr-gə-ˌniz-əm
: an organism of microscopic or ultramicroscopic size
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