allergy

American  

[al-er-jee] / ˈæl ər dʒi /

noun

allergies plural

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.

3. Informal. a strong dislike or aversion, as toward a person or activity.

   He has an allergy to hard work.

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allergy British  

/ ˈælədʒɪ /

noun

1. a hypersensitivity to a substance that causes the body to react to any contact with that substance. Hay fever is an allergic reaction to pollen

2. informal aversion

   he has an allergy to studying

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allergy Scientific  

/ ăl′ər-jē /

1. An abnormally high immunologic sensitivity to certain stimuli such as drugs, foods, environmental irritants, microorganisms, or physical conditions, such as temperature extremes. These stimuli act as antigens, provoking an immunological response involving the release of inflammatory substances, such as histamine, in the body. Allergies may be innate or acquired in genetically predisposed individuals. Common symptoms include sneezing, itching, and skin rashes, though in some individuals symptoms can be severe.

2. See also anaphylactic shock

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allergy Cultural  

1. A highly sensitive reaction of the body to certain substances, such as pollen, that are present in amounts that do not affect most people. Common indications of allergy include sneezing, skin rashes, itching, and runny nose.

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Other Word Forms

Inflected Forms

noun

• allergies
  plural

Etymology

Origin of allergy

1910–15; < Greek áll ( os ) other + -ergy < Greek -ergia, equivalent to érg ( on ) activity + -ia -y ³

Explanation

An allergy is a physical reaction to some specific food or substance. If you have an allergy to cats, they'll make you itchy and swollen no matter how much you love to pet them. If you have an allergy, it can range from mild — itchy eyes in the springtime — to serious — being unable to breathe after eating a peanut. People have allergies to all kinds of things, including milk, chocolate, corn, dust, mold, and just about any kind of animal you can think of. Allergy was originally Allergie, a German word invented by a doctor who combined the Greek roots allos, "other, different, or strange," and ergon, "activity."

Example Sentences

Helen Blythe has been campaigning for a law that would see compulsory training for teachers and a requirement for each school to have a dedicated allergy policy.

From BBC • Jun. 1, 2026

“Hell’s Kitchen,” a New York story of a wunderkind discovering her gift, helped me get over my allergy to the jukebox genre.

From Los Angeles Times • May 30, 2026

Across most facilities, detainees reported improperly cooked food, a lack of dietary or allergy accommodations and irregular mealtimes.

From Los Angeles Times • May 15, 2026

The treatment for Carey's walnut and pecan allergy cost £6,000, with a further £4,000 set aside for associated travel and hotel costs.

From BBC • Apr. 23, 2026

She has developed a random allergy to certain words.

From "How the García Girls Lost Their Accents" by Julia Alvarez

Related Words

• hay fever