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

memo function
memoisation
memoised function
memoization
memoized function

    (Or "memoised function") A function that
   remembers which arguments it has been called with and the
   result returned and, if called with the same arguments again,
   returns the result from its memory rather than recalculating
   it.

   Memo functions were invented by Professor Donald Michie of
   Edinburgh University.  The idea was further developed by
   Robin Popplestone in his Pop2 language long before it was
   ever worked into LISP.

   This same principle is found at the hardware level in computer
   architectures which use a cache to store recently accessed
   memory locations.

   A Common Lisp package by Marty Hall
   
   (ftp://archive.cs.umbc.edu/pub/Memoization).

   ["'Memo' functions: and machine learning", Donald Michie,
   Nature, 218, 19-22, 1968].

   (2002-07-02)