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
Favoring plant protein comes with a bonus, says Ben-Asher, because the dietary fiber and phytonutrients only found in plants is fuel for healthy microorganisms that colonize gut microbiota.
—
Rachel Reiff Ellis, SELF, 5 Feb. 2026
Improves Gut Health Some cottage cheese is fortified with probiotics, live microorganisms that improve the balance of bacteria in the body.
—Anna Giorgi, Verywell Health, 5 Feb. 2026
If food particles do get stuck, then there’s a risk of microorganism growth.
—Stacey Lastoe, Southern Living, 4 Feb. 2026
The recall includes Cheerios, Pringles, Coke, and more, with contamination from rodents, birds, and harmful microorganisms.
—Michele Laufik, Martha Stewart, 30 Jan. 2026
See All Example Sentences for microorganism
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Rachel Reiff Ellis, SELF, 5 Feb. 2026
Improves Gut Health Some cottage cheese is fortified with probiotics, live microorganisms that improve the balance of bacteria in the body.
—Anna Giorgi, Verywell Health, 5 Feb. 2026
If food particles do get stuck, then there’s a risk of microorganism growth.
—Stacey Lastoe, Southern Living, 4 Feb. 2026
The recall includes Cheerios, Pringles, Coke, and more, with contamination from rodents, birds, and harmful microorganisms.
—Michele Laufik, Martha Stewart, 30 Jan. 2026
See All Example Sentences for microorganism
Cite this Entry
“Microorganism.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/microorganism. Accessed 16 Feb. 2026.
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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