The Free On-line Dictionary of Computing (30 December 2018):

A-0

    (Or A0) A language for the UNIVAC I or II, using
   three-address code instructions for solving mathematical
   problems.  A-0 was the first language for which a compiler
   was developed.  It was produced by Grace Hopper's team at
   Remington Rand in 1952.  Later internal versions were A-1,
   A-2, A-3, AT-3.  AT-3 was released as MATH-MATIC.

   ["The A-2 Compiler System", Rem Rand, 1955].

   [Sammet 1969, p. 12].

   (1995-12-03)