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

Meanwhile, tea tree extract and lavender oil soothe inflammation, while clover flower extract provides antioxidant benefits and neutralizes free radical damage to improve overall skin texture. —Conçetta Ciarlo, Vogue, 17 Mar. 2025

These issues are exacerbated by the onslaught of free radicals found in urban pollution like NYC, as well as the environmental aggressors (i.e., severe weather, dryness and high altitudes) in Aspen. —Jessica Ourisman, Forbes, 3 Mar. 2025

Plus, maca root extract protects against free radical damage, while lactic acid gently exfoliates. —Conçetta Ciarlo, Vogue, 6 Mar. 2025

Nearly all plant foods contain antioxidants, which are chemical compounds that help remove harmful free radicals from our cells.4 Luteolin is one such chemical helper. —Sarah Garone, Health, 21 Feb. 2025

Word History

First Known Use

1870, in the meaning defined above

Rhymes for free radical

• radicle

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