allergen

noun

al·​ler·​gen ˈa-lər-jən 

: a substance (such as pollen) that induces allergy

allergenic

ˌa-lər-ˈje-nik 

adjective

allergenicity

ˌa-lər-jə-ˈni-sə-tē 

noun

Examples of allergen in a Sentence

common allergens, such as pollen

Recent Examples on the Web

Consult your pediatrician on how to introduce babies — and babies at risk of a severe allergy — to nuts and other allergens safely. —Cara Lynn Shultz, PEOPLE, 21 Oct. 2025

When in use, fans can disperse allergens into the air, so keeping them clean can help improve the air quality in your home and help allergy sufferers breathe better. —Karen Brewer Grossman, Southern Living, 20 Oct. 2025

Authors used real-world data to build on previous research suggesting that introducing children to peanut, egg, and other high-risk food allergens earlier in life than previously recommended could lower their risks of developing food allergies. —Beth Ann Mayer, Parents, 20 Oct. 2025

So, peanuts won’t be listed with the ingredients as a present allergen. —David J. Neal, Miami Herald, 19 Oct. 2025

Word History

Etymology

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

Note: See note at allergy.

First Known Use

circa 1907, in the meaning defined above

Kids Definition

allergen

noun

al·​ler·​gen ˈal-ər-jən 

: a substance (as pollen) that causes allergy

allergenic

ˌal-ər-ˈjen-ik 

adjective

Medical Definition

allergen

noun

al·​ler·​gen ˈal-ər-jən 

: a substance that induces allergy

inhaled allergens

a suspected food allergen