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

von Neumann integer

    A finite von Neumann ordinal.

   The von Neumann integer N is a finite set with N elements
   which are the von Neumann integers 0 to N-1.  Thus

   	0 = 		= 
   	1 = 0		= 
   	2 = 0, 1	= , 
   	3 = 0, 1, 2	= , , , 
   	...

   The set of von Neumann integers is infinite, even though
   each of its elements is finite.

   [Origin of name?]

   (1995-03-30)