23:  Where does the name "Emacs" come from?

  Emacs originally was an acronym for Editor MACroS.  RMS says he "picked
  the name Emacs because `E' was not in use as an abbreviation on ITS at
  the time."  The first Emacs was a set of macros written in 1976 at MIT by
  RMS for the editor TECO (Text Editor and COrrector, originally Tape
  Editor and COrrector) under ITS on a PDP-10.  RMS had already extended
  TECO with a "real-time" full screen mode with active keys.  Emacs was
  started by Guy Steele <gls@think.com> as a project to unify the many
  divergent TECO command sets and key bindings at MIT.

  Many people have said that TECO code looks a lot like line noise.  See
  alt.lang.teco if you are interested.  Someone has written a TECO
  implementation in Emacs Lisp (to find it, see question 87); it would be
  an interesting project to run the original TECO Emacs inside of Emacs.

  For some not-so-serious alternative reasons for Emacs to have that name,
  check out etc/JOKES (see question 4).