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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The buildup of free radicals, called oxidative stress, has been linked to cancer as well as diseases that affect the heart, kidney, brain and respiratory system, according to the Cleveland Clinic. Adrianna Rodriguez, USA TODAY, 6 Feb. 2025 This powder uses quinoa seed extract to minimize the appearance of pores while vitamin C helps protect against free radicals. Clare Holden, Glamour, 6 Feb. 2025 Avocado oil reduces unstable harmful molecules (free radicals) in rodent brains and increases the presence of antioxidant molecules.1 6. Amy Brownstein, Ms, Rdn, Verywell Health, 31 Jan. 2025 Multiple studies suggest anthocyanin is phenomenal at getting rid of free radicals in the body. Rowan Briggs, The Mercury News, 28 Jan. 2025 See all Example Sentences for free radical 

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 10 Feb. 2025.

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
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