Dictionary.com

free radical

Save This Word!

noun Chemistry, Biochemistry.
an atom or molecule that bears an unpaired electron and is extremely reactive, capable of engaging in rapid chain reactions that destabilize other molecules and generate many more free radicals: in the body, deactivated by antioxidants, uric acid, and certain enzyme activities.
QUIZ
WILL YOU SAIL OR STUMBLE ON THESE GRAMMAR QUESTIONS?
Smoothly step over to these common grammar mistakes that trip many people up. Good luck!
Question 1 of 7
Fill in the blank: I can’t figure out _____ gave me this gift.
Compare diradical.

Origin of free radical

First recorded in 1895–1900
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use free radical in a sentence

British Dictionary definitions for free radical

free radical

noun
an atom or group of atoms containing at least one unpaired electron and existing for a brief period of time before reacting to produce a stable moleculeSometimes shortened to: radical Compare group (def. 10)
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for free radical

free radical

An atom or group of atoms that has at least one unpaired electron and is therefore unstable and highly reactive. In animal tissues, free radicals can damage cells and are believed to accelerate the progression of cancer, cardiovascular disease, and age-related diseases.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
FEEDBACK