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

This helps prevent buildup and keeps allergens and airborne particles from circulating throughout your home. — Daley Quinn, Southern Living, 6 July 2026

Common allergens such as soy or nuts may be present in some varieties of plant proteins. — Anna Giorgi, Verywell Health, 3 July 2026

Dogs who don't shed as heavily or who have different coat textures are often referred to as hypoallergenic, but there is no consistent evidence that these breeds produce fewer allergens. — Madeline Gunderson, USA Today, 2 July 2026

To prevent moisture and body oils from breaking down the internal components (and keep stains and allergens at bay), investing in a quality mattress protector is one of the simplest and most effective ways to extend your mattress's lifespan. — Jamie Cuccinelli, Martha Stewart, 1 July 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