spirochete

noun

spi·​ro·​chete ˈspī-rə-ˌkēt How to pronounce spirochete (audio)
variants or less commonly spirochaete
: any of an order (Spirochaetales) of slender spirally undulating bacteria including those causing syphilis and Lyme disease

Examples of spirochete in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Ticks collected in California as early as 2000 were found to carry the new spirochete, for example. — Beth Mole, Ars Technica, 13 Apr. 2023 To this day, the mechanism of action of this malaria-on-syphilis, parasite-on-spirochete action is unknown (7). — Rebecca Kreston, Discover Magazine, 31 May 2014

Word History

Etymology

borrowed from New Latin Spirochaeta, bacterial genus, from Latin spīra "coil, twist, whorl" + Greek -o- -o- + chaítē "growth of hair, flowing locks" — more at spire entry 3, chaeta

Note: The genus was introduced by the German zoologist Christian Gottfried Ehrenberg (1795-1876) in "Dritter Beitrag zur Erkenntnis grosser Organisation in der Richtung des kleinsten Raumes," Physikalische Abhandlungen der Königlichen Akademie der Wissenschaften zu Berlin: aus dem Jahre 1833 (Berlin, 1835), p. 313. Ehrenberg had found the organism, which he named Spirochaeta plicatilis (Latin plicātilis "capable of being folded"), in water left from the previous winter ("im überwinterten Wasser") in Berlin on April 2, 1832.

First Known Use

circa 1877, in the meaning defined above

Time Traveler
The first known use of spirochete was circa 1877

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Cite this Entry

“Spirochete.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/spirochete. Accessed 26 Mar. 2025.

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Kids Definition

spirochete

noun
spi·​ro·​chete
variants also spirochaete
ˈspī-rə-ˌkēt How to pronounce spirochete (audio)
: any of a group of slender coiled bacteria including one that causes syphilis

Medical Definition

spirochete

noun
spi·​ro·​chete
variants or chiefly British spirochaete
ˈspī-rə-ˌkēt How to pronounce spirochete (audio)
: any bacterium of the order Spirochaetales including those causing syphilis and relapsing fever

More from Merriam-Webster on spirochete

Britannica.com: Encyclopedia article about spirochete

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