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

Our products are certified organic, allergen-free, nutrient-dense. —Dave Knox, Forbes.com, 11 June 2026

Low-allergen flowering shrubs can add low-maintenance color and interest to gardens. —Alexandra Jones, The Spruce, 10 June 2026

In Australia, infant feeding guidelines for allergy prevention were updated in 2016 to recommend introducing egg and other food allergens in the first year of life to reduce the risk of food allergy, according to the new study. —Jacqueline Howard, CNN Money, 8 June 2026

Black, Hispanic and Indigenous children are more vulnerable to asthma than white children, which might reflect high levels of allergens where some families live or difficulties in getting effective care. —Dr. Daniel Digiacomo, Boston Herald, 7 June 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