antioxidant

noun

an·​ti·​ox·​i·​dant ˌan-tē-ˈäk-sə-dənt 

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

Sunflower seeds provide significantly more vitamin E, an antioxidant that protects the brain from damage caused by free radicals. —Heather Jones, Verywell Health, 13 May 2026

Drinking green tea daily can improve your overall health, thanks to its antioxidants, caffeine, and calming L-theanine. —Kirsten Nunez, Martha Stewart, 12 May 2026

Almonds are especially high in vitamin E, an antioxidant that helps protect your cells from damage. —Brianna Tobritzhofer, Health, 12 May 2026

Nutritional Benefits Of Avocado Peel Avocados are packed with antioxidants and nutrients that are healthy for humans, but are the peels good for plants? —Brandee Gruener, Southern Living, 10 May 2026

Word History

First Known Use

1919, in the meaning defined above

Rhymes for antioxidant

• oxidant

Kids Definition

antioxidant

noun

an·​ti·​ox·​i·​dant ˌant-ē-ˈäk-səd-ənt 

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- 

: 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