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
Soil microorganisms are impacted by compaction, some of which are responsible for soil nutrient cycling.
—
Nora Doonan, Hartford Courant, 4 Apr. 2026
Probiotics are bacteria, yeast, and other microorganisms.
—Amber J. Tresca, Verywell Health, 4 Apr. 2026
The color of any body of water is affected by many factors, including depth and clarity, as well as the presence or absence of microorganisms like plankton.
—Stacey Leasca, Travel + Leisure, 4 Apr. 2026
Before the water reaches the membrane, the seawater is typically filtered to remove debris and microorganisms that could clog equipment.
—ABC News, 1 Apr. 2026
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Nora Doonan, Hartford Courant, 4 Apr. 2026
Probiotics are bacteria, yeast, and other microorganisms.
—Amber J. Tresca, Verywell Health, 4 Apr. 2026
The color of any body of water is affected by many factors, including depth and clarity, as well as the presence or absence of microorganisms like plankton.
—Stacey Leasca, Travel + Leisure, 4 Apr. 2026
Before the water reaches the membrane, the seawater is typically filtered to remove debris and microorganisms that could clog equipment.
—ABC News, 1 Apr. 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 8 Apr. 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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