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
Your gut microbiome is the community of trillions of microorganisms (such as fungi, bacteria, and viruses) that live in your gut.
—
Cynthia Sass, Health, 21 Oct. 2025
On face value, this seems counterproductive for even a microorganism, where replication and in turn genetic survival is a driving force.
—New Atlas, 16 Oct. 2025
Harmful bacteria and other microorganisms could have infiltrated the city's water system due to the recent water main breaks, according to the City of Globe Water Department and Gila County Public Health and Community Services.
—Helen Rummel, AZCentral.com, 16 Oct. 2025
Get ready to dive into a cosmos of blooming microorganisms!
—Georg Szalai, HollywoodReporter, 16 Oct. 2025
See All Example Sentences for microorganism
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Cynthia Sass, Health, 21 Oct. 2025
On face value, this seems counterproductive for even a microorganism, where replication and in turn genetic survival is a driving force.
—New Atlas, 16 Oct. 2025
Harmful bacteria and other microorganisms could have infiltrated the city's water system due to the recent water main breaks, according to the City of Globe Water Department and Gila County Public Health and Community Services.
—Helen Rummel, AZCentral.com, 16 Oct. 2025
Get ready to dive into a cosmos of blooming microorganisms!
—Georg Szalai, HollywoodReporter, 16 Oct. 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 29 Oct. 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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