atom

 
Pronunciation: /ˈatəm/

noun

  • 1the smallest particle of a chemical element that can exist.
  • (usually the atom) atomic particles as a source of nuclear energy: the power of the atom
  • [usually with negative] an extremely small amount of something: I shall not have one atom of strength left
  • 2 [usually as modifier] Canadian a level of amateur sport, typically involving children aged between nine and eleven: eight atom hockey teams

Origin:

late 15th century: from Old French atome, via Latin from Greek atomos 'indivisible', based on a- 'not' + temnein 'to cut'