English

Definition of radical noun from the Oxford Advanced Learner's Dictionary

      

    radical

     noun
    noun
    BrE BrE//ˈrædɪkl//
     
    ; NAmE NAmE//ˈrædɪkl//
     
    Terrorism
     
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  1. 1 a person with radical opinions political radicals See related entries: Terrorism
  2. 2 (chemistry) a group of atoms that behave as a single unit in a number of compounds see also free radical
  3. Word Origin late Middle English (in the senses ‘forming the root’ and ‘inherent’): from late Latin radicalis, from Latin radix, radic- ‘root’.
See the Oxford Advanced American Dictionary entry: radical