diphtheria

noun

diph·​the·​ria dif-ˈthir-ē-ə How to pronounce diphtheria (audio)
nonstandard
dip- How to pronounce diphtheria (audio)
: an acute febrile contagious disease typically marked by the formation of a false membrane especially in the throat and caused by a gram-positive bacterium (Corynebacterium diphtheriae) that produces a toxin causing inflammation of the heart and nervous system
diphtherial
dif-ˈthir-ē-əl How to pronounce diphtheria (audio)
nonstandard dip-
adjective
diphtheritic
ˌdif-thə-ˈri-tik How to pronounce diphtheria (audio)
nonstandard ˌdip-
adjective

Examples of diphtheria 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.
Cases of whooping cough, polio, smallpox, rubella and diphtheria fell by 99-100% after vaccinations for each became standard. — Business Columnist, Los Angeles Times, 12 Aug. 2026 At that point, the CDC recommended children receive a vaccine against smallpox, a combination vaccine against diphtheria, tetanus and pertussis, known as the DTP vaccine, and a vaccine against polio. — Jake Scott, The Conversation, 12 Aug. 2026 Most vaccines, including the tetanus-diphtheria jab used in the trial, must be refrigerated or frozen. — Paige Bruton, semafor.com, 10 Aug. 2026 Vaccines in the executive order’s first group—those recommended for all children—include vaccines for measles, mumps, rubella, diphtheria, tetanus and pertussis, as well as human papillomavirus (HPV) and polio, among other conditions. — Jackie Flynn Mogensen, Scientific American, 10 Aug. 2026 See All Example Sentences for diphtheria

Word History

Etymology

New Latin, from French diphthérie, from Greek diphthera leather; from the toughness of the false membrane

First Known Use

circa 1851, in the meaning defined above

Time Traveler
The first known use of diphtheria was circa 1851

Rhymes for diphtheria

See All Rhymes for diphtheria

Browse Nearby Words

diphosphothiamine
diphtheria
diphtheroid
See all Nearby Words

Cite this Entry

“Diphtheria.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/diphtheria. Accessed 17 Aug. 2026.

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Kids Definition

diphtheria

noun
diph·​the·​ria dif-ˈthir-ē-ə How to pronounce diphtheria (audio) dip- How to pronounce diphtheria (audio)
: a contagious bacterial disease with fever in which the air passages become coated with a membranous layer that often obstructs breathing
diphtheritic
ˌdif-thə-ˈrit-ik How to pronounce diphtheria (audio)
ˌdip-
adjective

Medical Definition

diphtheria

noun
diph·​the·​ria dif-ˈthir-ē-ə How to pronounce diphtheria (audio) dip- How to pronounce diphtheria (audio)
: an acute febrile contagious disease typically marked by the formation of a false membrane especially in the throat and caused by a bacterium of the genus Corynebacterium (C. diphtheriae) which produces a toxin causing inflammation of the heart and nervous system
diphtherial
-ē-əl How to pronounce diphtheria (audio)
adjective

More from Merriam-Webster on diphtheria

Nglish: Translation of diphtheria for Spanish Speakers

Britannica.com: Encyclopedia article about diphtheria

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