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

combinatory logic

    A system for reducing the operational notation of
   logic, mathematics or a functional language to a sequence
   of modifications to the input data structure.  First
   introduced in the 1920's by Schoenfinkel.  Re-introduced
   independently by Haskell Curry in the late 1920's (who
   quickly learned of Schoenfinkel's work after he had the idea).
   Curry is really responsible for most of the development, at
   least up until work with Feys in 1958.

   See combinator.

   (1995-01-05)