What is the meaning of Allergy?

A disorder of the immune system causing adverse reactions to substances (allergens) not harmful to most and marked by the body's production of histamines and associated with atopy, anaphylaxis, and asthma; any condition of hypersensitivity to a substance.

  1. Specifically, hypersensitivity of class I in the modern classification thereof: the immunoglobulin E–mediated type.

Specifically, hypersensitivity of class I in the modern classification thereof: the immunoglobulin E–mediated type.

An antipathy, as toward a person or activity.

Source: wiktionary.org