Word Study
allergen
OXFORD DICTIONARY
allergen, n. any substance that causes an allergic reaction.
Derivative
allergenic adj.
Etymology
ALLERGY + -GEN
THESAURUS
allergen
Rh factor, agglutinin, allergic disorder, allergy, anaphylactin, antiantibody, antibody, antigen, antiserum, antitoxic serum, antitoxin, antivenin, asthma, conjunctivitis, cosmetic dermatitis, eczema, hay fever, hives, incomplete antibody, interferon, pollinosis, precipitin, rose cold, serum, urticariaFor further exploring for "allergen" in Webster Dictionary Online