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

DiLuigi Foods discovered lot numbers that start with 16B21 and 16C21 of DiLuigi Smashables The Original Style Smashburger don’t have milk listed among the allergens on the label. —David J. Neal, Miami Herald, 4 June 2026

The inspection revealed that manufacturing processes required improvements to prevent allergen cross-contact. —Michelle Del Rey, USA Today, 1 June 2026

Scott Schrader, cleaning expert at CottageCare, explains how sheets can become a hotbed for bacteria and allergens fairly quickly in the summer because sweat, body oils, dust mites, and skin cells accumulate quickly from excessive heat and humidity. —Sheila Kim, The Spruce, 31 May 2026

Use these six easy steps to remove dirt, pollutants, and allergens from outdoor rugs and mats. —Nafeesah Allen, Better Homes & Gardens, 31 May 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