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

How Often To Wash Sheets After that initial wash, get into the habit of washing your sheets weekly to get rid of allergens, dead skin, and bacteria. —Melissa Locker, Southern Living, 16 Feb. 2026

Bamboo-viscose is also naturally repellent to odors and allergens, making this set a great choice for people with sensitive skin, too. —Jasmine Gomez, Travel + Leisure, 16 Feb. 2026

Cleaning with steam can kill dust mites, bacteria, and germs, reduces allergens, and deodorizes by breaking down odor-causing bacteria. —Madeline Buiano, Martha Stewart, 15 Feb. 2026

Lack of food safety training costs points: Restaurants are often penalized for missing certifications or inadequate staff training in hygiene, allergens and safe food handling, issues experts say are preventable with proper education. —Evan Moore, Charlotte Observer, 13 Feb. 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