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


The relative size of A1 paper.


  • (paper size): Specified in ISO 216.



  1. (international standards) ISO 216 standard paper size of 594 mm × 841 mm (23.39 in × 33.11 in), with a surface area of 0.5 m2 (5.38 sq ft).
  2. (finance) Long-term bond credit rating by Moody's Investors Service, indicating that a bond is upper-medium grade with low risk of default.

See also[edit]


Etymology 1[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 2[edit]


A1 (plural A1s)

  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.


Norwegian Bokmål[edit]

Norwegian Bokmål Wikipedia has an article on:
Wikipedia nb
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Please see that page for discussion and justifications. You may continue to edit this entry while the discussion proceeds, but please mention significant edits at the RFD discussion and ensure that the intention of votes already cast is not left unclear. Do not remove the {{rfd}} until the debate has finished.


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


  • IPA(key): /ˈɑːeːn/
  • (file)
  • Rhymes: -eːn
  • Hyphenation: A‧1


A1 (uncountable)

  1. A1 (a standard paper size, defined by ISO 216)

See also[edit]