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
Nature is rife with naturally occurring ethanol, particularly from ripening fruit, and that fruit in turn is consumed by various microorganisms and animal species.
—
ArsTechnica, 18 Sep. 2025
Kefir is a good source of probiotic microorganisms, such as lactic acid bacteria (LAB), which could benefit digestive health.
—Jillian Kubala, Health, 17 Sep. 2025
Crucially, these viruses are specific to their hosts, and those targeting nitrifiers shouldn’t harm other microorganisms in the soil.
—Katherine Bourzac, Quanta Magazine, 15 Sep. 2025
On Earth, such compounds often form when microorganisms consume organic material.
—Gabe Whisnant, MSNBC Newsweek, 10 Sep. 2025
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ArsTechnica, 18 Sep. 2025
Kefir is a good source of probiotic microorganisms, such as lactic acid bacteria (LAB), which could benefit digestive health.
—Jillian Kubala, Health, 17 Sep. 2025
Crucially, these viruses are specific to their hosts, and those targeting nitrifiers shouldn’t harm other microorganisms in the soil.
—Katherine Bourzac, Quanta Magazine, 15 Sep. 2025
On Earth, such compounds often form when microorganisms consume organic material.
—Gabe Whisnant, MSNBC Newsweek, 10 Sep. 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 1 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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