Dictionary.com
Thesaurus.com
Synonyms

allergen

American  
[al-er-juhn, -jen] / ˈæl ər dʒən, -ˌdʒɛn /

noun

Immunology.
  1. any substance, often a protein, that induces an allergy: common allergens include pollen, grasses, dust, and some medications.


allergen British  
/ ˈæləˌdʒɛn /

noun

  1. any substance capable of inducing an allergy

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

allergen Scientific  
/ ăl′ər-jən /
  1. A substance, such as pollen, that causes an allergic reaction.


Other Word Forms

Etymology

Origin of allergen

First recorded in 1910–15; aller(gy) + -gen

Vocabulary lists containing allergen

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

It meets regularly with Cava insiders to advise on topics such as how to safely add seafood to the menu, which is an allergen for some, Tolivar said.

From The Wall Street Journal ● Aug. 25, 2026

If you’re never exposed to an allergen, you can’t develop an allergy, and this would result in fewer allergies in the community, the theory went.

From Slate ● Dec. 3, 2025

The team discovered that when pest control successfully reduced cockroach numbers, both allergen and endotoxin levels dropped sharply.

From Science Daily ● Nov. 4, 2025

An estimated 40,000 children avoided peanut allergy diagnoses after the guidelines for when to first expose kids to the food allergen changed, according to new research.

From Los Angeles Times ● Oct. 20, 2025

Every touchable surface was a disease waiting to happen, every speck of dust an allergen poised to swell your nose and clog your ducts, every toothbrush bristle a bacterial playground.

From "The Mysterious Benedict Society" by Trenton Lee Stewart

Vocabulary.com logo
by dictionary.com

Dictionary.com's Learning Companion

Go beyond just looking up words.
Remember them forever with VocabTrainer.

Start training