free-radical
|free-rad-i-cal|
/ˌfriːˈrædɪkəl/
unbound reactive unit
Etymology
'free radical' originates from English, formed from the two words 'free' + 'radical', where 'free' meant 'not bound' and 'radical' comes from Latin 'radicalis' (from 'radix') meaning 'root'.
'radical' changed from Latin 'radicalis' via Old French into Middle English as 'radical'; in 19th-century chemistry 'radical' came to mean a group or root-like part of a molecule, and the compound term 'free radical' emerged in the late 19th to early 20th century to describe an unbound, reactive species.
Initially it meant 'of the root' or 'root-like', but over time in chemistry it evolved to mean 'a reactive species with an unpaired electron'; figuratively it later came to mean 'an independent or extreme person.'
Meanings by Part of Speech
Noun 1
in chemistry, an atom, molecule, or molecular fragment that has one or more unpaired electrons and is typically highly reactive.
A free-radical can damage cells by reacting with DNA.
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Noun 2
figuratively, a person who holds extreme views or acts independently of established groups; a maverick.
After repeatedly breaking with party policy, he was called a free-radical.
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Adjective 1
relating to or characteristic of free radicals; involving or caused by unpaired electrons (often used in scientific contexts), or describing radical/extreme tendencies.
Free-radical chemistry examines how unstable molecules react.
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Last updated: 2025/11/10 07:41