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

Unlike many baffle-box down duvets, this one is conveniently machine-washable and allergen-free. —Blake Bakkila, Architectural Digest, 9 Mar. 2026

The label for Don Gollo Bakery brand sugar cookies was missing the ingredient declaration, including allergens food coloring and soybean. —David J. Neal, Miami Herald, 8 Mar. 2026

Linens, mattresses, and upholstered furniture can harbor dust mites, allergens, or even bacteria that are nearly impossible to remove. —Ashley Poskin, Martha Stewart, 7 Mar. 2026

Each ingredient is diligently vetted and each product is exhaustively tested (including a microbial analysis) for heavy metals, pesticides, solvent residues, environmental contaminants, and common allergens including gluten. —Brianna Peters, Vogue, 6 Mar. 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