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

Noun Inflected Forms

• 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

See Examples For:

allergy allergies

Still others described unexplained rashes, outbreaks of diarrhea and infestations of lice, among a host of other maladies for which many said they were offered only Tylenol or allergy medication.

From Los Angeles Times ● Jul. 24, 2026

Continued demand for its allergy, haemophilia A and breast cancer drugs were among the key growth drivers, it said.

From The Wall Street Journal ● Jul. 23, 2026

The other is in the US - although cases of the allergy have since been noted on all six continents where ticks live.

From BBC ● Jul. 20, 2026

New York City Mayor Zohran Mamdani revealed last year he was undergoing allergy shots so his wife, Rama Duwaji, could one day welcome a cat into Gracie Mansion.

From The Wall Street Journal ● Jul. 6, 2026

Janice, my oldest sister, had an allergy that made one nostril sing like a bird at night, so we called her Whistling Nose.

From "The Joy Luck Club" by Amy Tan

Cosmo itched so much from allergies that he constantly scratched himself raw and unleashed a howl when we were gone for too long, so loud and haunting that my neighbor thought it was a siren.

From Los Angeles Times ● Jul. 28, 2026

Rowley struggled to find work as a bookkeeper because so many locations triggered her allergies.

From BBC ● Jul. 20, 2026

An unhealthy microbial balance has been associated with a higher risk of allergies, depression, anxiety, and neurodegenerative diseases, including Alzheimer's disease.

From Science Daily ● Jul. 10, 2026

Approved by the Food and Drug Administration in 2024 for all food allergies, the drug helps reduce allergic reactions after accidental exposures.

From The Wall Street Journal ● Jun. 25, 2026

"Have you ever had a brother who had allergies that kept you from having a dog?"

From "The View From Saturday" by E.L. Konigsburg

Related Words

• hay fever