from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A substance, such as pollen, that causes an allergy.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A substance which causes an allergic reaction.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. any substance that can cause an allergy
German Allergen : Aller(gie), allergy; see allergy + -gen, -gen (from French -gène; see -gen).(American Heritage® Dictionary of the English Language, Fourth Edition)