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

This whisper-quiet air purifier is designed to tackle mold, dust, smoke, and other allergens in large spaces of up to 3,048 square feet. —Stephanie Osmanski, Better Homes & Gardens, 10 Nov. 2025

Indoor air can contain pollen, allergens, pet dander, odor, dust, and more. —Karen Brewer Grossman, Southern Living, 9 Nov. 2025

Ice cream bars sold at Kroger and Giant Eagle stores in Ohio, Kentucky and several other states are being recalled by their manufacturer due to an allergen. —Chad Murphy, Cincinnati Enquirer, 5 Nov. 2025

For Thanksgiving, Annie May's, which prepares all its items on Celiac safe and top nine allergen free equipment, is offering pumpkin pie ($30), cheesecake ($30), 9-inch fruit pies in a variety of flavors ($32), icebox pies ($33) and pumpkin cheesecake tart ($33). —Kathryn Gregory, Louisville Courier Journal, 4 Nov. 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