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A hint of the Greek word bios, meaning "life", can be seen in microbe. Microbes, or microorganisms, include bacteria, protozoa, fungi, algae, amoebas, and slime molds. Many people think of microbes as simply the causes of disease, but every human is actually the host to billions of microbes, and most of them are essential to our life. Much research is now going into possible microbial sources of future energy; algae looks particularly promising, as do certain newly discovered or created microbes that can produce cellulose, to be turned into ethanol and other biofuels.

Examples of microbe in a Sentence

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In fact, even though there wasn't a lot of carbon dioxide in the tank, the microbes persisted, adapting to the conditions relatively quickly. — Chelsea Gohd, Space.com, 25 Sep. 2026 Ordinarily, the placenta does a magnificent job of keeping microbes away from a developing fetus. — Mike McRae 24, New Atlas, 25 Sep. 2026 Alltech’s Optigen is a slow-release source of nonprotein nitrogen urea designed to feed the rumen microbes over time, while Novus’s Zn is a zinc chelate more available than conventional inorganic sources. — Aidan Connolly, Forbes.com, 25 Sep. 2026 In future studies, the team hopes to look even closer at how frogs acquire protective skin microbiomes from the natural environment, with the goal of safeguarding tropical habitats that support the beneficial microbes. — Laura Baisas, Popular Science, 24 Sep. 2026 See All Example Sentences for microbe

Word History

Etymology

International Scientific Vocabulary micr- + Greek bios life — more at quick entry 1

First Known Use

1878, in the meaning defined above

Time Traveler
The first known use of microbe was in 1878

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Cite this Entry

“Microbe.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/microbe. Accessed 27 Sep. 2026.

Medical Definition

: microorganism, germ
—used especially of pathogenic bacteria
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