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

The star ingredients here are oil-absorbing clays (including kaolin and bentonite) and the brand’s signature grapeseed polyphenols, which provide free radical protection as well as combat sebum oxidation—the reason blackheads appear dark. —Emily Orofino, Vogue, 21 Nov. 2024

Ginger also contains many potent anti-inflammatory compounds and antioxidants—substances that protect the body from oxidative stress and free radicals. —Lana Barhum, Verywell Health, 21 Nov. 2024

Mushrooms also contain an antioxidant known as selenium, which fights damaging free radicals that could otherwise contribute to aging, cancer and heart disease. —Daryl Austin, USA TODAY, 16 Nov. 2024

These compounds protect cells against free radical damage, according to the source. —Ashlyn Messier, Fox News, 10 Oct. 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