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

Free2b produces chocolate sun cups free from top allergens, and No Whey Foods covers chocolate truffles and candy bars that are dairy-free, nut-free and vegan. —Allison Palmer, Kansas City Star, 30 Mar. 2026

Although eating an allergen is the most common and important trigger of severe allergic reactions, there are also other ways to come in contact with a food allergen. —Dr. Sonja O'Leary, Boston Herald, 29 Mar. 2026

These allergens can pose serious or potentially life‑threatening risks to individuals with food allergies. —Amanda Greenwood, MSNBC Newsweek, 29 Mar. 2026

Food produced without inspection may contain undeclared allergens, harmful bacteria or other contaminants, according to the FSIS. —Greta Cross, USA Today, 27 Mar. 2026

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