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

One of the reasons why education and awareness about TB are so important is that a person with latent TB may be unknowingly harboring the microorganism for years. —Karen Dobos, The Conversation, 6 Mar. 2025

There are materials to cultivate micro-algae as a potential food source; the tools needed to test how microorganisms affect different surfaces inside the orbiting lab; and the equipment to create advanced semiconductor crystals. —Robert Z. Pearlman, Space.com, 1 Mar. 2025

Probiotics contain live microorganisms that increase the amount of beneficial microbes in our body, which help fight bad bacteria and keep us healthy. —Saman Shafiq, USA TODAY, 19 Feb. 2025

The Appeal of Probiotics for Athletes We are surrounded by microorganisms. —Julia Ries, Outside Online, 29 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