antioxidant

noun

an·​ti·​ox·​i·​dant ˌan-tē-ˈäk-sə-dənt How to pronounce antioxidant (audio)
ˌan-ˌtī-
: a substance (such as beta-carotene or vitamin C) that inhibits oxidation or reactions promoted by oxygen, peroxides, or free radicals
antioxidant adjective

Examples of antioxidant in a Sentence

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.
Plant Compounds in Peel-On Cucumbers Cucumbers contain polyphenols, flavonoids, and ascorbic acid, all of which act as antioxidants in your body. — Angelica Bottaro, Verywell Health, 29 Oct. 2026 While the colloidal gold soothes inflammation and nourishes the skin with antioxidants, hexapeptides smooth out the appearance of fine lines and wrinkles, while damask rose helps strengthen the skin barrier. — Lauren Valenti, Vogue, 29 Oct. 2026 The complex also contains a blend of antioxidants, flax seed extract, and acetyl tetrapeptide-2, which work together to improve skin elasticity, maximize hydration, and even out the skin tone across the neck and décolleté. — Christa Joanna Lee, Glamour, 23 Oct. 2026 These antioxidants may help lower oxidative stress, inflammation, and fat buildup in the liver. — Lindsey Desoto, HEALTH, 23 Oct. 2026 See All Example Sentences for antioxidant

Word History

First Known Use

1919, in the meaning defined above

Time Traveler
The first known use of antioxidant was in 1919

Rhymes for antioxidant

See All Rhymes for antioxidant

Browse Nearby Words

anti-organization
antioxidant
antioxygen
See all Nearby Words

Cite this Entry

“Antioxidant.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/antioxidant. Accessed 31 Oct. 2026.

Copy Citation

Kids Definition

antioxidant

noun
an·​ti·​ox·​i·​dant ˌant-ē-ˈäk-səd-ənt How to pronounce antioxidant (audio)
ˌan-ˌtī-
: a substance that opposes oxidation or prevents or makes difficult reactions made easier by oxygen

Medical Definition

antioxidant

noun
an·​ti·​ox·​i·​dant ˌant-ē-ˈäk-səd-ənt, ˌan-ˌtī- How to pronounce antioxidant (audio)
: any of various substances (as beta-carotene, vitamin C, and alpha-tocopherol) that inhibit oxidation or reactions promoted by oxygen and peroxides and that include many held to protect the living body from the deleterious effects of free radicals
antioxidant adjective

More from Merriam-Webster on antioxidant

Britannica.com: Encyclopedia article about antioxidant

Love words? Need even more definitions?

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

Last Updated: - Updated example sentences

More from Merriam-Webster

Word of the Day

Listen to the pronunciation of wraith

See Definitions and Examples »

Popular in Grammar & Usage

See More

How to Use 'Who' vs. 'Whom'

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

'Affect' vs. 'Effect'

'A' or 'an'? What about before 'h'? An Indefinite Article Guide

Why is '-ed' sometimes pronounced at the end of a word?
See More

Popular in Wordplay

See More

The Longest Long Words List

9 Words That Sound Like Insults But Aren't

Pwn, Skibidi, Girlboss and Other Words Added to the 2026 Scrabble Dictionary

The Words of the Week - Oct. 30

12 Lovely and Unusual Words for the Natural World
See More

Popular

See More

How to Use 'Who' vs. 'Whom'

The Longest Long Words List

9 Words That Sound Like Insults But Aren't
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
different halloween monsters in silhouette
A Monstrous Vocab Quiz Words That Go Bump in the Night
See All