The Free On-line Dictionary of Computing (30 December 2018):
Interface Description Language
   (IDL) A language designed by Nestor, Lamb and Wulf of CMU in
   1981 for describing the data structures passed between parts
   of an application, to provide a language-independent
   intermediate representation.
   It forms part of Richard Snodgrass 's
   Scorpion environment development system.
   Not to be confused with any of the other IDLs.
   Mailing list: info-idl@sei.cmu.edu.
   ["The Interface Description Language: Definition and Use," by
   Richard Snodgrass, Computer Science Press, 1989, ISBN
   0-7167-8198-0].
   [SIGPLAN Notices 22(11) (Nov 1987) special issue].
   (1994-11-11)