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

These sublethal effects can be compared to the way an over-the-counter antihistamine may relieve allergy symptoms while also causing drowsiness.

From Science Daily ● Aug. 6, 2026

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

Van Nunen's biggest concern, though, is the 85% of people who have the allergy without knowing it – people who have developed the antibodies but who do not react after eating meat.

From BBC ● Jul. 20, 2026

In addition to the daily multitude, those amateur cooks were faced with allergy cases, diabetics, nursing mothers, infants who required special feedings.

From "Farewell to Manzanar" by Jeanne Houston

Ask your guests about their allergies and snack preferences then put together a snack basket.

From Los Angeles Times ● Jul. 23, 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

Benedict, from Stamford, Lincolnshire, had asthma and a number of allergies, including eggs, nuts and milk.

From BBC ● Jul. 5, 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

As for the negatives, she talks a lot about allergies and weird hobbies, like the kid who collects movie ticket stubs.

From "The Miscalculations of Lightning Girl" by Stacy McAnulty

Related Words

• hay fever