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

mimencode

   (Originally distributed as "mmencode").  A replacement for
   uuencode for use in electronic mail and news.  Part of
   MIME.  uuencode uses characters that don"t translate well
   across all mail gateways (particularly those which convert
   between ASCII and EBCDIC).  Also, different variants of
   uuencode encode data in different and incompatible ways, with
   no standard.  Finally, few uuencode variants work well in a
   pipe.  Mimencode implements the encodings which were defined
   for MIME as uuencode replacements, and should be
   considerably more robust for e-mail use.  Written by Nathaniel
   S. Borenstein of Bell Communications Research,
   Inc. (Bellcore) in 1991.