microorganism

American  

[mahy-kroh-awr-guh-niz-uhm] / ˌmaɪ kroʊˈɔr gəˌnɪz əm /

noun

1. any organism too small to be viewed by the unaided eye, as bacteria, protozoa, and some fungi and algae.

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microorganism British  

/ ˌmaɪkrəʊˈɔːɡəˌnɪzəm /

noun

1. any organism, such as a bacterium, protozoan, or virus, of microscopic size

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microorganism Scientific  

/ mī′krō-ôr′gə-nĭz′əm /

1. An organism that can be seen only with the aid of a microscope and that typically consists of only a single cell. Microorganisms include bacteria, protozoans, and certain algae and fungi.

2. See Note at germ

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Other Word Forms

• microorganic adjective
• microorganismal adjective

Etymology

Origin of microorganism

First recorded in 1875–80; micro- + organism

Example Sentences

Because they are now known to be present throughout the ocean, they likely move through entire food webs, from microorganisms to fish and ultimately to humans.

From Science Daily

Until recently, scientists had limited understanding of how the microorganisms in sourdough interact with these fibers.

From Science Daily

This microorganism is frequently used in laboratory studies because it possesses an extremely small genome.

From Science Daily

Unlike soil on Earth, it does not contain microorganisms or organic matter that plants depend on to grow.

From Science Daily

Scientists believe these adaptable microorganisms, which rely heavily on iron and carry out ammonia oxidation, could significantly influence how nutrients are distributed throughout the oceans as the climate continues to change.

From Science Daily

Related Words

• bacterium
• microbe
• pathogen
• virus