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

Next, medications that contain allergens like peanuts, milk and eggs can potentially cause allergic reactions. —Kurt Knutsson, FOXNews.com, 26 Sep. 2025

These incidents underscore the importance of vigilance in food distribution and the potential dangers when allergen or contamination risks reach the national marketplace. —Daniel Orton, MSNBC Newsweek, 24 Sep. 2025

Opening September 25th, Bub’s Bakery is a new concept that offers pastries, sweets and savory items free of all major allergens. —Leigh Nordstrom, Footwear News, 23 Sep. 2025

For serious allergens, always check a product’s manufacturer to see if it’s made in a facility that comes in contact with other allergens. —Sophia Beams, Better Homes & Gardens, 23 Sep. 2025

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