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See also: a2 and A-2


Alternative forms[edit]

  • (cardiology): A2


  • For the paper size sense, see the Wikipedia article ISO 216, the international standard on paper sizes.



  1. A standard paper size, defined by ISO 216; dimensions: 594 x 420 mm.
  2. (virology) A type of Asian influenza virus.
    • 1877, John Holmes Dingle, 'Biographical Memoirs', volume 61 (in English):
      [] antibody response to Influenza (A2) virus.
  3. (cardiology) Aortic second sound.
    • 2012, Perloff, Joseph K.; Marelli, Ariane, Perloff's Clinical Recognition of Congenital Heart Disease (in English):
      [] and the aortic component of the second sound (A2) is normal.

See also[edit]