allergy: Meaning and Definition of

al•ler•gy

1. an abnormal reaction of the body to a previously encountered allergen introduced by inhalation, ingestion, injection, or skin contact, often manifested by itchy eyes, runny nose, wheezing, skin rash, or diarrhea.
2. hypersensitivity to the reintroduction of an allergen. Cf. anaphylaxis.
3. a strong dislike or aversion, as toward a person or activity: He has an allergy to hard work.