V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

EGREP
       Extended Global Regular Expression Print (Unix, GREP)


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

egrep

    An extended version of the Unix grep command.
   Egrep accepts extended regular expressions (REs) including
   "*" following multi-character REs; "+" (one or more matches);
   "?"  (zero or one matches); "|" separating two REs matches
   either.  REs may be bracketed with ().  Despite its additional
   complexity, egrep is usually faster than fgrep or grep.

   (2004-07-20)