[al-er-juh n, -jen]

noun Immunology.

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

Origin of allergen

First recorded in 1910–15; aller(gy) + -gen Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Related Words for allergen

dander, irritant, pollen, antigen, ragweed

British Dictionary definitions for allergen



any substance capable of inducing an allergy
Derived Formsallergenic, adjectiveallergenicity, noun
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

Word Origin and History for allergen

substance causing allergy, 1912, from allergy on model of antigen.

Online Etymology Dictionary, © 2010 Douglas Harper

allergen in Medicine




A substance, such as pollen, that causes an allergy.
Related formsal′ler•genic (-jĕnĭk) adj.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

allergen in Science



A substance, such as pollen, that causes an allergic reaction.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.