al·​ler·​gen | \ ˈa-lər-jən How to pronounce allergen (audio) \

Definition of allergen

: a substance (such as pollen) that induces allergy

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Other Words from allergen

allergenic \ ˌa-​lər-​ˈje-​nik How to pronounce allergen (audio) \ adjective
allergenicity \ ˌa-​lər-​jə-​ˈni-​sə-​tē How to pronounce allergen (audio) \ noun

Examples of allergen in a Sentence

common allergens, such as pollen
Recent Examples on the Web That inquiry has centered on one of the official ingredients, polyethylene glycol, which is very rarely an allergen. Michael Segal, WSJ, "Facebook’s Censors and the Ingredients List," 22 Dec. 2020 Another thing to keep in mind is the symptoms of anaphylaxis usually appear pretty quickly after a person has been exposed to an allergen. Kate Baggaley, Popular Science, "What you should know about allergic reactions to the COVID-19 vaccine," 17 Dec. 2020 One theory is that an overactive immune system can cause the release of histamine, similar to what happens when the body encounters an allergen. Allyson Chiu, Washington Post, "Covid may cause rashes and swelling. That doesn’t mean you’re ‘allergic,’ experts say.," 2 Dec. 2020 It is equipped with an allergen filter and features greater suction power, as well as two brushless rollers — a feature that is specifically useful for pet owners. NBC News, "Home Depot Black Friday 2020: Best Home Depot deals to shop," 9 Nov. 2020 First-time allergic reactions are challenging to prepare for and symptoms can appear just minutes after exposure to an allergen. Corryn Wetzel, Smithsonian Magazine, "Allergic Reactions to Peanuts and Tree Nuts Spike 85 Percent on Halloween," 29 Oct. 2020 This allergen is transferred to fur when cats lick themselves while grooming. Birnur Aral, Ph.d., Good Housekeeping, "GH Seal Spotlight: Purina Pro Plan LiveClear Cat Food," 15 Sep. 2020 It’s allergen-friendly—free of tree nuts, soy, and gluten. Carolyn L. Todd, SELF, "The Oat Milk Craze Isn't Going Anywhere," 6 Aug. 2020 The allergen typically emerges around Labor Day, and keeps allergy sufferers sneezing through the first snowfall. Mary Kilpatrick, cleveland, "Ragweed season is coming to Northeast Ohio," 2 Aug. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'allergen.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of allergen

circa 1907, in the meaning defined above

History and Etymology for allergen

borrowed from German Allergen,, blend of allerg- (in Allergie allergy) and -gen (in Antigen antigen)

Note: See note at allergy.

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Time Traveler for allergen

Time Traveler

The first known use of allergen was circa 1907

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Statistics for allergen

Last Updated

30 Dec 2020

Cite this Entry

“Allergen.” Dictionary, Merriam-Webster, Accessed 24 Jan. 2021.

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More Definitions for allergen


How to pronounce allergen (audio)

English Language Learners Definition of allergen

medical : a substance that causes an allergy


al·​ler·​gen | \ ˈa-lər-jən How to pronounce allergen (audio) \

Kids Definition of allergen

: a substance that causes an allergic reaction


al·​ler·​gen | \ ˈal-ər-jən How to pronounce allergen (audio) \

Medical Definition of allergen

: a substance that induces allergy inhaled allergens a suspected food allergen

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More from Merriam-Webster on allergen

Nglish: Translation of allergen for Spanish Speakers

Britannica English: Translation of allergen for Arabic Speakers Encyclopedia article about allergen

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