allergy
UK /ˈæl.ə.dʒi/ US /ˈæl.ɚ.dʒi/ Syllables: al-ler-gy
Quick answer
A condition in which the body reacts badly to a normally harmless substance, such as pollen or certain foods.
An allergy is a condition in which the body reacts badly to something that is usually harmless, such as pollen, dust, nuts or milk. A person with an allergy may sneeze, get a rash or find it hard to breathe. Some allergies are mild, and some can be dangerous. A doctor can test you to find out what you are allergic to. If you have a food allergy, you must read labels carefully and tell people who cook for you.
"He carries medicine with him because of his allergy to peanuts."Example sentences
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"She has an allergy to peanuts, so she reads every label."
Level A2
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"My brother's allergy makes him sneeze in spring."
Level A2
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"Do you have any food allergies?"
Level A1
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"The doctor tested me for an allergy to cats."
Level B1
Look-alikes and common mistakes
- intolerance : A food intolerance upsets the stomach. An allergy involves the body's defense system and can be much more serious.
- infection : An infection is caused by germs. An allergy is a reaction to a harmless substance.
Word family and forms
Forms: allergies
Word partners
Words and phrases that often go with "allergy".
- a food allergy
- a nut allergy
- hay fever allergy
- have an allergy
- an allergy test
- a severe allergy
Origin
Allergy was coined in 1906 by an Austrian doctor, who borrowed it into German as Allergie from two Greek words: allos, meaning other, and ergon, meaning work or action. The idea was a changed reaction, a different way of working. English took the word around 1910.
Checked against: Wiktionary, the free dictionary, Dictionary.com.
Usage notes
The adjective form is "allergic", as in "allergic to peanuts", not "allergy to peanuts."
How to remember it
Allergy has two l's and a g that sounds like j: AL-er-jee. Say it slowly and picture a sneeze.
Test yourself
Which word fits the gap? "She has an _____ to peanuts, so she reads every label."
Answer: allergy
In your own words, what does "allergy" mean?
A condition in which the body reacts badly to a normally harmless substance, such as pollen or certain foods.
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Sources and credits
- Wiktionary, the free dictionary (CC BY-SA 4.0) · used for the origin · checked Oct 19, 2026
- Dictionary.com · used for the origin · checked Oct 19, 2026
Last reviewed October 20, 2026. Report a mistake on this page