allergen

noun

al·​ler·​gen ˈa-lər-jən How to pronounce allergen (audio)
: a substance (such as pollen) that induces allergy
allergenic
ˌa-lər-ˈje-nik How to pronounce allergen (audio)
adjective
allergenicity
ˌa-lər-jə-ˈni-sə-tē How to pronounce allergen (audio)
noun

Examples of allergen in a Sentence

common allergens, such as pollen
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Most thrift stores won’t accept them due to concerns about bedbugs, allergens, and general hygiene. — Nafeesah Allen, Better Homes & Gardens, 26 July 2026 The drug works by blocking a neurotransmitter called acetylcholine, which can help calm the body’s response to allergens. — Andrew Yockey, The Conversation, 24 July 2026 The signature blend of ceramides works to strengthen and support the skin’s natural barrier, which helps lock in moisture while defending against environmental irritants like pollutants and allergens. — Alicia Geigel, Southern Living, 23 July 2026 Regular cleaning keeps dirt and allergens from building up on your tile floors. — Tessa Cooper, The Spruce, 21 July 2026 See All Example Sentences for allergen

Word History

Etymology

borrowed from German Allergen,, blend of allerg- (in Allergie allergy) and -gen (in Antigen antigen)

Note: See note at allergy.

First Known Use

circa 1907, in the meaning defined above

Time Traveler
The first known use of allergen was circa 1907

Browse Nearby Words

Allen wrench
allergen
allergic
See all Nearby Words

Cite this Entry

“Allergen.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/allergen. Accessed 1 Aug. 2026.

Copy Citation

Kids Definition

allergen

noun
al·​ler·​gen ˈal-ər-jən How to pronounce allergen (audio)
: a substance (as pollen) that causes allergy
allergenic
ˌal-ər-ˈjen-ik How to pronounce allergen (audio)
adjective

Medical Definition

allergen

noun
al·​ler·​gen ˈal-ər-jən How to pronounce allergen (audio)
: a substance that induces allergy
inhaled allergens
a suspected food allergen

More from Merriam-Webster on allergen

Nglish: Translation of allergen for Spanish Speakers

Britannica.com: Encyclopedia article about allergen

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

More from Merriam-Webster

Word of the Day

Listen to the pronunciation of spindrift

See Definitions and Examples »

Popular in Grammar & Usage

See More

7 Pairs of Commonly Confused Words

Merriam-Webster’s Great Big List of Words You Love to Hate

Is it 'nerve-racking' or 'nerve-wracking'?

Why does English have so many silent letters?

Your vs. You're: How to Use Them Correctly
See More

Popular in Wordplay

See More

Dutch Treat and French Leave: Eight Place-Based Compounds

14 Phobias You Probably Haven't Heard Of

The Longest Long Words List

The Words of the Week - Jul. 31

Even More Bird Names that Sound Like Insults (and Sometimes Are)
See More

Popular

See More

7 Pairs of Commonly Confused Words

Dutch Treat and French Leave: Eight Place-Based Compounds

14 Phobias You Probably Haven't Heard Of
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
asap street sign
Figure Out These Acronyms ASAP You don't have to be a NASA engineer to get these...
See All