allergy

American  

[al-er-jee] / ˈæl ər dʒi /

noun

plural

allergies

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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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

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

Professor Adam Fox, who specialises in paediatric allergy, said allergies now had "major public health implications for millions of people".

From BBC • Apr. 23, 2026

The Food Standards Agency advises people with an allergy visiting a restaurant to be upfront with the eatery and make sure it is able to make the changes to suit any dietary needs.

From BBC • Apr. 15, 2026

Because the bot remembers you have a nut allergy, it won’t suggest noodles with peanut sauce.

From The Wall Street Journal • Apr. 11, 2026

“Walk into any drugstore. Makeup and candy up front, tampons and condoms in the back, by the pharmacy, close to the allergy and flu medications.”

From "Tradition" by Brendan Kiely

Related Words

• hay fever