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 Oils that are repeatedly heated, such as canola oil used in deep-fat frying, also contain harmful compounds like free radicals. Jillian Kubala, Rd, Health, 10 July 2024 Stress In studies where pregnant mice were given a small amount of energy drink daily during their pregnancy, newborn mice had oxidative stress (when free radicals lead to cell and tissue damage), tissue injury, and anxiety. Chaunie Brusie, Rn, Bsn, Parents, 1 July 2024 These sprouts help the body produce more antioxidants, protecting cells from free radical damage. Sandra Rose Salathe, Flow Space, 28 June 2024 That process converts the particles into something known as free radicals, which can damage cells and tissues. Janet Loehrke, USA TODAY, 21 June 2024 See all Example Sentences for free radical 

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'free radical.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1870, in the meaning defined above

Time Traveler
The first known use of free radical was in 1870

Dictionary Entries Near free radical

Cite this Entry

“Free radical.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/free%20radical. Accessed 19 Jul. 2024.

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

More from Merriam-Webster on free radical

Last Updated: - Updated example sentences
Love words? Need even more definitions?

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