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

Definition of allergen

: a substance (such as pollen) that induces allergy

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 An allergy is when the immune system reacts to a foreign substance, called an allergen. cleveland, 12 May 2022 Everything is naturally vegan and made in a top allergen free dedicated facility. Essence, 26 Apr. 2022 The pork and beef tamales the USDA recalled last week contained sesame, which is a common allergen. Chris Smith, BGR, 30 Oct. 2021 This allergen, fragrance, and oil-free body wash has been specially created for individuals with hypersensitive skin and hair. Grooming Playbook, The Salt Lake Tribune, 7 Apr. 2022 When the furry felines clean themselves, the allergen is spread all over their fur and can become airborne when their coat dries, reports Michael Le Page for New Scientist. Elizabeth Gamillo, Smithsonian Magazine, 31 Mar. 2022 Type 3 allergic reactions can happen when proteins from an allergen attach to your protective antibodies. Marygrace Taylor, SELF, 29 Mar. 2022 The reaction's placement can inform which part of the device causes the problem, and an allergist- or dermatologist-issued allergy patch test can confirm the allergen. Dana Rose Falcone, Allure, 16 Mar. 2022 But the packaging does not mention the presence of the allergen, as seen in the images below. Chris Smith, BGR, 10 Mar. 2022 See More

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.

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.

Buying Guide

Our Reviews team has selected the best vacuums for allergies.

Learn More About allergen

Time Traveler for allergen

Time Traveler

The first known use of allergen was circa 1907

See more words from the same year

Dictionary Entries Near allergen

Allen wrench



See More Nearby Entries 

Statistics for allergen

Last Updated

17 May 2022

Cite this Entry

“Allergen.” Dictionary, Merriam-Webster, Accessed 28 May. 2022.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

More Definitions for allergen


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

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


Test Your Vocabulary

Eponyms: Words Named After People

True or False

Test your knowledge - and maybe learn something along the way.

Universal Daily Crossword

A daily challenge for crossword fanatics.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!