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

Prebiotics are infused with plant fibers that feed microorganisms living in our guts. —Saman Shafiq, USA TODAY, 19 Feb. 2025

Probiotic supplements contain live microorganisms that help balance the good bacteria, improving digestion and supporting immune function. —Chelsea Rae Bourgeois, Rdn, Health, 10 Feb. 2025

If food particles do get stuck, then there’s a risk of microorganism growth. —Stacey Lastoe, Southern Living, 6 Feb. 2025

This voluntary recall is not related to an allergen, microorganism, or any pathogen contamination, and no other Horizon Organic products are affected. —Sari Hitchins, Parents, 24 Jan. 2025

Word History

Etymology

International Scientific Vocabulary

First Known Use

1880, in the meaning defined above

Rhymes for microorganism

• absolutism
• adventurism
• aestheticism
• africanism
• agnosticism
• alcoholism
• anabolism
• anachronism
• anglicanism
• antagonism
• arianism
• asceticism

Kids 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