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

Without deep cleaning spaces or items (such as small appliances), a host of problems occur from the inevitable accumulation of dust, allergens, bacteria, germs, soap scum, mold and mildew. —Mary Marlowe Leverette, The Spruce, 13 Jan. 2026

But take precautions while enjoying the cooler weather this weekend as cedar pollen will be plentiful, thanks to the passage of the cold front and breezy winds to spread the airborne allergens. —Mary Wasson, Austin American Statesman, 10 Jan. 2026

Right now, the company says Allergen Alert can only test for gluten and dairy, but there are plans to expand to other common allergens. —Tom Gavin, EverydayHealth.com, 9 Jan. 2026

Jarvis recommends that homes with allergy prone occupants have air ducts cleaned every two years for better indoor air quality and minimize allergen exposure. —Lauren David, Southern Living, 8 Jan. 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