allergy
Americannoun
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allergies
plural
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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.
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hypersensitivity to the reintroduction of an allergen.
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Informal. a strong dislike or aversion, as toward a person or activity.
He has an allergy to hard work.
noun
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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
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informal aversion
he has an allergy to studying
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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.
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See also anaphylactic shock
Other Word Forms
Noun Inflected Forms
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."
Vocabulary lists containing allergy
National Nurses Week: Medical Branches and Conditions
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This Week In Words: Current Events Vocab for February 6–12, 2021
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This Week in Words: Current Events Vocabulary for July 29–August 4, 2023
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
The family of a 12-year-old girl who died after drinking a milkshake made in an unwashed blender at a cafe have called for a dedicated rating that scores food businesses on their allergy management.
From BBC ● Oct. 8, 2026
Natasha's Foundation founder Tanya Ednan-Laperouse, whose daughter died aged 15 from an allergy to sesame in a Pret A Manger baguette, said allergies were "a serious, unpredictable medical condition".
From BBC ● Oct. 8, 2026
It wasn’t painful, but after several weeks I developed alpha-gal syndrome, an increasingly common allergy to red meat, dairy and other mammalian food products.
From Los Angeles Times ● Oct. 4, 2026
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
I couldn’t help my allergy to electronic stuff.
From "Sir Fig Newton and the Science of Persistence" by Sonja Thomas
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It also found nearby restaurants that could deliver food, taking into account any allergies of the attendees.
From The Wall Street Journal ● Oct. 8, 2026
Meanwhile, conditions like allergies often don’t show up until a pet is 2 or 3 years old, Quammen said.
From MarketWatch ● Sep. 15, 2026
For six-and-a-half years, Lisa Hayden-Johnson claimed Matthew had a long list of illnesses including diabetes, food allergies, cerebral palsy and cystic fibrosis, but years later it emerged she had made it all up.
From BBC ● Aug. 19, 2026
But please do not do this if you have allergies, or are likely to get stung.
From Science Daily ● Jul. 29, 2026
And Nigeria is not a nation of people with food allergies, not a nation of picky eaters for whom food is about distinctions and separations.
From "Americanah" by Chimamanda Ngozi Adichie
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Get a wordDefinitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.