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

Multipurpose Internet Mail Extensions
MIME

    (MIME) A standard for multi-part,
   multimedia electronic mail messages and web
   hypertext documents on the Internet.  MIME provides the
   ability to transfer non-textual data, such as graphics,
   audio and fax.  It is defined in RFC 2045, RFC 2046,
   RFC 2047, RFC 2048, RFC 2049, and BCP0013.  It uses
   mimencode to encode binary data into base 64 using a
   subset of ASCII.

   FAQ

(http://cis.ohio-state.edu/hypertext/faq/usenet/mail/mime-faq/top.html).

   (1995-04-04)