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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
Oxidative stress is the imbalance between free radicals (reactive molecules that can damage cells and genetic material) and antioxidants in the body.
—Lana Barhum, Verywell Health, 31 Oct. 2024
Meet free radicals: unstable oxygen molecules—generated by exposure to external factors like environmental pollution and UV rays—that damage cellular structures like DNA, lipids, and proteins.
—Abby Dupes, StyleCaster, 20 Sep. 2024
They might be best known as antioxidants (which fend off cell-damaging molecules called free radicals), but newer research suggests they’re also fermented by your friendly gut bacteria, further supporting a healthy microbiome.
—Erica Sloan, SELF, 4 Sep. 2024
Antioxidants—like curcumin—work by binding to and neutralizing free radicals, thus reducing the risk of cellular damage that can lead to disease.
—Sarah Bence, Verywell Health, 28 Oct. 2024
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Word History
First Known Use
1870, in the meaning defined above
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 28 Nov. 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
Britannica.com: Encyclopedia article about free radical
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