free radical: meaning, definition, pronunciation and examples
C1-C2Technical (primarily Chemistry, Biochemistry, Medicine, Health), sometimes used figuratively in journalism and social commentary.
Quick answer
What does “free radical” mean?
A highly reactive molecule with an unpaired electron, capable of causing damage to cells.
Audio
Pronunciation
Definition
Meaning and Definition
A highly reactive molecule with an unpaired electron, capable of causing damage to cells.
Any highly reactive, unconstrained, or disruptive entity in a system; often used metaphorically in non-scientific contexts to describe a destabilizing force or person.
Dialectal Variation
British vs American Usage
Differences
No significant differences in scientific meaning or usage. Minor potential differences in the prominence of the term in public health/consumer contexts (e.g., 'anti-oxidants combat free radicals').
Connotations
Equally negative in scientific contexts (damaging). In metaphorical use, can be negative (destabilizing) or slightly positive (radical, independent thinker), though the negative connotation dominates.
Frequency
Equal frequency in scientific registers. Slightly higher public exposure in American media related to health supplements and skincare marketing.
Grammar
How to Use “free radical” in a Sentence
Free radicals [VERB: damage/attack/oxidise] [NOUN: cells/DNA].[NOUN: Antioxidants/Compounds] [VERB: neutralise/scavenge] free radicals.Free radicals are [ADJECTIVE: formed/generated/produced] by [NOUN: process].Vocabulary
Collocations
Usage
Meaning in Context
Business
Figurative: 'The new CEO was seen as a free radical, disrupting the traditional corporate culture.'
Academic
Primary usage: 'The study examined the role of free radicals in the ageing process of mitochondrial DNA.'
Everyday
Often in health/beauty contexts: 'This cream has antioxidants to protect your skin from free radicals.'
Technical
Precise definition: 'A hydroxyl free radical (•OH) is the most reactive species in aqueous radiation chemistry.'
Vocabulary
Synonyms of “free radical”
Neutral
Weak
Vocabulary
Antonyms of “free radical”
Watch out
Common Mistakes When Using “free radical”
- Incorrect pluralisation: 'free radicals' (correct), not 'free radical'.
- Using 'free radical' as a positive term in science (it is inherently damaging).
- Confusing it with general 'toxins' or 'impurities'.
FAQ
Frequently Asked Questions
In biology, they are generally harmful, causing oxidative stress. However, the immune system uses some free radicals to destroy pathogens, and they are essential intermediates in many industrial chemical processes.
In precise usage, a 'radical' is any atom or molecule with an unpaired electron. A 'free radical' specifically implies this radical is freely existing and not part of a bound transition state during a reaction, though the terms are often used interchangeably.
Yes, but it is a metaphorical use. It describes a person who acts independently and disruptively, challenging established norms, often with a slightly negative or wary connotation (e.g., 'a free radical in the political party').
They are natural byproducts of metabolism (like energy production in mitochondria). External sources include UV radiation, tobacco smoke, air pollution, and certain chemicals.
A highly reactive molecule with an unpaired electron, capable of causing damage to cells.
Free radical is usually technical (primarily chemistry, biochemistry, medicine, health), sometimes used figuratively in journalism and social commentary. in register.
Free radical: in British English it is pronounced /ˌfriː ˈræd.ɪ.kəl/, and in American English it is pronounced /ˌfri ˈræd.ə.kəl/. Tap the audio buttons above to hear it.
Learning
Memory Aids
Mnemonic
Think of a 'free' electron 'radically' unattached, making the molecule desperate to steal an electron from anything nearby, like a tiny chemical vandal.
Conceptual Metaphor
CHEMICAL INSTABILITY IS A VANDAL/AGGRESSOR; A DESTABILIZING PERSON/FORCE IS A FREE RADICAL.
Practice
Quiz
In which field is the term 'free radical' primarily and most precisely defined?