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

Regular washing removes allergens, germs, and buildup from skin, dust, and pet hair. — Sheila Kim, The Spruce, 18 Sep. 2026

Intrinsic is separately working with materials technology company HeiQ to explore combining Ciclo fibers with cooling, faster-drying, odor-control and allergen-reduction treatments. — Alexandra Harrell, Footwear News, 17 Sep. 2026

The recall comes days after a separate recall by Whole Foods of a specialty cheese item due to an undeclared allergen. — Chiara Kim, PEOPLE, 17 Sep. 2026

California residents are tracking a rising rabies threat, a grocery recall over an undeclared allergen and new traffic-calming work in a Sacramento-area suburb. — Sacbee.com, 15 Sep. 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