allergy

noun

al·​ler·​gy ˈa-lər-jē 

plural allergies

1

: altered bodily reactivity (such as hypersensitivity) to an antigen in response to a first exposure

a bee venom allergy so severe that a second sting may be fatal

2

: exaggerated or pathological immunological reaction (as by sneezing, difficult breathing, itching, or skin rashes) to substances, situations, or physical states that are without comparable effect on the average individual

3

: medical practice concerned with allergies

4

: a feeling of antipathy or aversion

Synonyms of allergy

• dislike
• hatred
• disliking
• distaste

Examples of allergy in a Sentence

Many people have some form of allergy.

independent-minded people who seem to have an allergy to any control from the government

Recent Examples on the Web

In 2018, Frankel, who suffers from a rare fish allergy, went into anaphylactic shock and spent several days in the ICU after eating soup that unknowingly contained fish flakes. —Vivian Kwarm, Mercury News, 23 Jan. 2026

Bacteria can grow, allergies can worsen, and your skin may become itchy or irritated. —Karen Brewer Grossman, Southern Living, 22 Jan. 2026

There are important considerations, including cleanliness, allergies, and the well-being of the animals themselves. —Itay Hod, CBS News, 20 Jan. 2026

For cedar pollen immunotherapy — whether traditional allergy shots or drops placed under the tongue — allergists often recommend starting six to 12 months ahead of the season. —Miriam Fauzia, Dallas Morning News, 20 Jan. 2026

Word History

Etymology

borrowed from German Allergie "heightened reaction to an antigen to which an individual has been previously exposed," from all- all- + -ergie, in Energie energy, or directly from its source, Greek -ergeia, taken to mean "action, response"

Note: The term was introduced, along with allergisch allergic and Allergen allergen, by the German physician Clemens Peter Freiherr von Pirquet (1874-1929) in "Allergie," Münchener medizinische Wochenschrift, 53. Jahrgang, Nr. 30 (July 24, 1906), pp. 1457-58.

First Known Use

1908, in the meaning defined at sense 1

Phrases Containing allergy

• allergy shot
• anti-allergy

Kids Definition

allergy

noun

al·​ler·​gy ˈal-ər-jē 

plural allergies

1

: exaggerated or abnormal reaction (as by sneezing, itching, or rashes) to substances, situations, or physical states that do not have such a strong effect on most people

2

: a feeling of dislike

Medical Definition

allergy

noun

al·​ler·​gy ˈal-ər-jē 

plural allergies

1

: altered bodily reactivity (as hypersensitivity) to an antigen in response to a first exposure

his bee-venom allergy may render a second sting fatal

2

: exaggerated or pathological reaction (as by sneezing, respiratory embarrassment, itching, or skin rashes) to substances, situations, or physical states that are without comparable effect on the average individual

3

: medical practice concerned with allergies