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

BBN Butterfly

    A supercomputer developed at BBN Technologies,
   named after the "butterfly" multi-stage switching network
   around which it was built.  It could have up to 512 CPUs
   connected to allow every CPU access to every other CPU's
   memory, albeit with about 15 times the latency than for its
   own.  The earlier GP-1000 models used up to 256 Motorola
   68020s.  The later TC-2000 models used up to 512 Motorola
   88100s.

   Language developed for, or ported to, the BBN Butterfly were
   Butterfly Common LISP, Butterfly Scheme, Delirium, and
   MultiScheme.

   (http://paralogos.com/DeadSuper/Misc/BBN.html).

   (2003-11-10)