chlamydia

noun

chla·myd·ia klə-ˈmi-dē-ə

plural chlamydiae klə-ˈmi-dē-ˌē

: any of a genus (Chlamydia, family Chlamydiaceae) of spherical gram-negative intracellular bacteria

especially : one (C. trachomatis) that causes or is associated with various diseases of the eye and urogenital tract including trachoma, lymphogranuloma venereum, cervicitis, and some forms of urethritis

: a disease or infection caused by chlamydiae

chlamydial

klə-ˈmi-dē-əl

adjective

Examples of chlamydia 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.

Rates of syphilis, gonorrhea, and chlamydia have climbed to levels not seen in a generation. — Rasheed Gonga, New York Daily News, 22 June 2026 The coffee shops are multiplying like chlamydia. — Dominic Green, The Washington Examiner, 20 Mar. 2026 For chlamydia and gonorrhea, treatment is a straightforward course of antibiotics. — Geri Stengel, Forbes.com, 30 Mar. 2026 Australian regulators approved the University of the Sunshine Coast’s vaccine for koala chlamydia. — Rafil Kroll-Zaidi, Harpers Magazine, 23 Nov. 2025 See All Example Sentences for chlamydia

Word History

Etymology

borrowed from New Latin, originally the name of a group, from Greek chlamyd-, chlamýs "mantle, chlamys" + New Latin -ia -ia entry 1

Note: The taxon Chlamydia was originally assigned to a group of microorganisms neither bacterial nor viral by Helen Jones, Geoffrey Rake, and Barbara Stearns in "Studies on lymphogranuloma venereum III. The action of the sulfonamides on the agent of lymphogranuloma venereum," Journal of Infectious Diseases, vol. 76, issue 1 (January, 1945), pp. 55-69. The choice of the element chlamyd- was presumably based on the earlier taxon Chlamydozoa (with -zoa -zoa) originated by Ludwig Halberstädter and Stanislaus von Prowazek, "Über Zelleinschlüsse parasitärer Natur beim Trachom," Arbeiten aus dem Kaiserlichen Gesundheitsamte, vol. 26, Heft 1 (1907), pp. 44-47.

First Known Use

1966, in the meaning defined at sense 1

Time Traveler

The first known use of chlamydia was in 1966

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Style

“Chlamydia.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/chlamydia. Accessed 7 Jul. 2026.

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Medical Definition

chlamydia

noun

chla·myd·ia klə-ˈmid-ē-ə

capitalized : the type genus of the family Chlamydiaceae comprising coccoid to spherical gram-negative intracellular parasitic bacteria and including one (C. trachomatis) that causes or is associated with various diseases of the eye and genitourinary tract including trachoma, lymphogranuloma venereum, cervicitis, and some forms of nongonococcal urethritis

plural chlamydiae -ē-ˌē, -ˌī also chlamydias

: a bacterium of the genus Chlamydia

: an infection or disease caused by a bacterium of the genus Chlamydia

chlamydial

-ē-əl

adjective

chlamydia

noun

Examples of chlamydia in a Sentence

Word History

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