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See also: a1, A-1, and A 1


Etymology 1[edit]

See the Wikipedia article ISO 216, the international standard on paper sizes.



  1. A standard paper size, defined by ISO 216 to have dimensions: 841 x 594 mm (840.90 x 594.60 mm)
    a sheet of A1 paper
See also[edit]

Etymology 2[edit]

From various rating systems, as that of Lloyd's of London or the condition of insured ships. First attested in 1837.

Alternative forms[edit]


A1 (not comparable)

  1. (informal) In good health.
  2. (informal) In excellent or top condition.
  3. (of a ship) First-class. (Compare A 2 and A 3, which are inferior grades.)

Etymology 3[edit]

Proper noun[edit]


  1. Under the International Union of Railways ("UIC") classification system, a steam locomotive that has two coupled driving wheels followed by two trailing wheels, with no leading wheels; also called an 0-2-2.