allergyan abnormal reaction of the body to an allergen, manifested by runny nose, skin rash, wheezing, etc.; hypersensitivity to the reintroduction of an allergenNot to be confused with:allergen ? any substance that induces an allergy, such as pollen, grasses, certain foods, and medicationsallergic ? pertaining to an allergy: allergic to peanutsAbused, Confused, & Misused Words by Mary Embree Copyright © 2007, 2013 by Mary Embreeal·ler·gy (?l??r-j?)n. pl. al·ler·gies 1. A condition in which exposure to a substance, such as pollen, latex, animal dander, or a particular food or drug, causes an overreaction by the immune system that results in symptoms such as sneezing, itching, rash, and difficulty breathing or swallowing.2. Informal An adverse sentiment; antipathy: an allergy to cocktail parties.[German Allergie : Greek allos, other; see allo- + Greek ergon, action; see werg- in Indo-European roots.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.allergy (?æl?d??) n, pl -gies1. (Pathology) a hypersensitivity to a substance that causes the body to react to any contact with that substance. Hay fever is an allergic reaction to pollen2. informal aversion: he has an allergy to studying. [C20: from German Allergie (indicating a changed reaction), from Greek allos other + ergon activity]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014al?ler?gy (?æl ?r d?i) n., pl. -gies. 1. an overreaction of the immune system to a previously encountered, ordinarily harmless substance, resulting in skin rash, swelling of mucous membranes, sneezing or wheezing, or other abnormal conditions. 2. Informal. a strong dislike or aversion: an allergy to hard work. [1910?15;