free radical

noun

A molecule, ion or atom that has one or more unpaired electrons, and which is generally highly reactive (and therefore often occurs only as a transient species).

Similar
radical
Ask AI about this wordChatGPTClaudePerplexityGoogle AIGrok

Meanings

nounfree radical (plural free radicals)

plural free radicals

  1. chemistryA molecule, ion or atom that has one or more unpaired electrons, and which is generally highly reactive (and therefore often occurs only as a transient species).

Synonyms & antonyms

nounan atom or group of atoms with at least one unpaired electron; in the body it is usually an oxygen molecule that has lost an electron and will stabilize itself by stealing an electron from a nearby molecule

Similar
radical
Broader
atom
Also see
radical

Synonym sets from Open English WordNet, CC BY 4.0.

Translations

Chinese Mandarin 自由基
  • 自由基 (zìyóujī)molecule, ion, or atom with an unpaired electron
Finnish vapaa radikaali
  • vapaa radikaalimolecule, ion, or atom with an unpaired electron
French radical libre
  • radical libremolecule, ion, or atom with an unpaired electron
German Radikal, freies Radikal
  • Radikalmolecule, ion, or atom with an unpaired electron
  • freies Radikalmolecule, ion, or atom with an unpaired electron
Hungarian szabad gyök
  • szabad gyökmolecule, ion, or atom with an unpaired electron
Indonesian radikal bebas
  • radikal bebasmolecule, ion, or atom with an unpaired electron
Italian radicale libero
  • radicale liberomolecule, ion, or atom with an unpaired electron
Japanese 遊離基
  • 遊離基 (yūriki)molecule, ion, or atom with an unpaired electron
Korean 유리기
  • 유리기 (yurigi)molecule, ion, or atom with an unpaired electron
Persian رادیکال آزاد
  • رادیکال آزاد (râdikâl-e âzâd)molecule, ion, or atom with an unpaired electron
Polish wolny rodnik
  • wolny rodnikmolecule, ion, or atom with an unpaired electron
Portuguese radical livre
  • radical livremolecule, ion, or atom with an unpaired electron
Spanish radical libre
  • radical libremolecule, ion, or atom with an unpaired electron
Ukrainian ві́льний радика́л
  • ві́льний радика́л (vílʹnyj radykál)molecule, ion, or atom with an unpaired electron
Vietnamese gốc tự do
  • gốc tự domolecule, ion, or atom with an unpaired electron
Welsh radical rhydd
  • radical rhyddmolecule, ion, or atom with an unpaired electron
Cite this entry
APA

free radical. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/free%20radical

MLA

“free radical.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/free%20radical. Accessed November 4, 2026.

Chicago

WatkinsX Dictionary, s.v. “free radical,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/free%20radical.

Source: free radical on Wiktionary, CC BY-SA 4.0.