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

Normally, mucus works with tiny hair-like cells in the nose to trap allergens and germs. —Brian Mastroianni, Health, 23 Feb. 2026

Consider fall the sweet spot, with cooler air, lower humidity, and fewer airborne allergens. —Mary Cornetta, Better Homes & Gardens, 21 Feb. 2026

Health benefits of house burping House burping can help remove contaminants such as carbon dioxide buildup, dust, allergens and gases from cleaning products and air fresheners from the home. —Alex Perry, Cincinnati Enquirer, 19 Feb. 2026

Those that fear dust mites and other allergens will be pleased to know this $40 pick from Quince impersonates hotel luxury pillows without the goose down or the price point. —Kate McGregor, Architectural Digest, 19 Feb. 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