General Science

  • adjective referring to a mathematical root of another number or quantity


  • An atom or molecule which has one or more unpaired electrons. Radicals are usually highly reactive and unstable. Also called free radical.
  • A group of atoms, such as a hydroxyl group, which reacts as a single unit.
  • Arising from, oriented towards, or pointing to an origin, root, or source.


  • adjective aiming to deal with the root of a problem, taking thorough action to remove the source of a disease rather than treat its symptoms
  • adjective referring to an operation which removes the whole of a part or of an organ, together with its lymph system and other tissue


  • adjective extreme or involving great change
  • adjective concerned with the most important or basic parts of something
  • noun a person who believes that a complete change should be made to society to reduce social problems
  • noun a member or supporter of a Radical Party


  • adjective excellent. In the 1980s the word moved from its political sense, via ‘radical chic’, to a generalised meaning of admirable in adolescent speech. It is now usually shortened to rad.

Origin & History of “radical”

Etymologically, radical means ‘of roots’. Its modern political meaning, based on the metaphor of fundamental change, going to the ‘roots’ of things, did not begin to emerge until the 18th century. The word was borrowed from late Latin rādīcālis, a derivative of Latin rādīx ‘root’ (source of English radish (OE) and probably related to root).