free radical

noun

: an especially reactive atom or group of atoms that has one or more unpaired electrons

especially : one that is produced in the body by natural biological processes or introduced from an outside source (such as tobacco smoke, toxins, or pollutants) and that can damage cells, proteins, and DNA by altering their chemical structure

Examples of free radical in a Sentence

Recent Examples on the Web

Vitamin E can help to protect the cells in the eye from free radicals and thus also reduce their sensitivity to bright light. —Maria Berentzen, Vogue, 12 Dec. 2024

Lilac stem cells also help fight free radicals and curb excess oil production without drying out skin, while two types of marine algae increase hydration and support the skin's natural collagen production. —Jennifer Hussein, Allure, 11 Dec. 2024

Rice water contains antioxidants, which can help fight free radicals in your body. —Julie Marks, Verywell Health, 10 Dec. 2024

These antioxidants are integral for fighting free radicals, and reducing inflammation in the body, per Healthline. —Caroline C. Boyle, USA TODAY, 6 Dec. 2024

Word History

First Known Use

1870, in the meaning defined above

Medical Definition

free radical

noun

: an especially reactive atom or group of atoms that has one or more unpaired electrons

especially : one that is produced in the body by natural biological processes or introduced from outside (as in tobacco smoke, toxins, or pollutants) and that can damage cells, proteins, and DNA by altering their chemical structure