[ al-er-juh n, -jen ]
/ ˈæl ər dʒən, -ˌdʒɛn /

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

British Dictionary definitions for allergen


/ (ˈæləˌdʒɛn) /


any substance capable of inducing an allergy

Derived Forms

allergenic, 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

Medicine definitions for allergen


[ ălər-jən ]


A substance, such as pollen, that causes an allergy.

Related forms

al′ler•genic (-jĕnĭk) adj.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for allergen


[ ălər-jən ]

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.