V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

REXX
       Restructured EXtended eXecutor [language] (IBM, SAA, ANSI)


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

Restructured EXtended eXecutor
REXX
System Product Interpreter

    (REXX, or "System Product Interpreter", originally
   known as "REX") A scripting language for IBM VM and MVS
   systems, developed by M. Cowlishaw at IBM ca. 1979,
   replacing EXEC2.

   Versions: PC-Rexx for MS-DOS, AREXX for the Amiga, the
   OS/2 implementation from IBM, WINREXX (Rexx for Windows,
   from Quercus systems) and Personal Rexx (Rexx for MS-DOS,
   from Quercus systems).

   See also Regina, freerexx, imc.

   REXXWARE is an implementation of REXX for Novell
   NetWare.

   Usenet newsgroup: news:comp.lang.rexx.

   ["The REXX Language: A Practical Approach to Programming",
   M.F. Cowlishaw, 1985].

   (1992-05-13)