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

And, as expected from Vanicream (which is known for its ultra-gentle formulas), the serum is fragrance-free and formulated without common allergens like dyes and lanolin. — Deanna Pai, Vogue, 2 Sep. 2026

Several foods, supplements and pet products were recalled in August over concerns ranging from possible salmonella and listeria contamination to undeclared allergens, foreign materials and other potential hazards. — Sacbee.com, 2 Sep. 2026

The molecule also exists on malaria parasites; the researchers had been trying to identify allergen-specific monoclonal antibodies to neutralize infection, but none could bind well to the parasite. — Theresa Gaffney, STAT, 2 Sep. 2026

Harrison added that the recall has nothing to do with an allergen, microorganism or pathogen contamination. — Saleen Martin, USA Today, 31 Aug. 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