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

electronic mail address
e-ddress
e-mail address

    (Usually "e-mail address") The string used to
   specify the source or destination of an electronic mail
   message.  E.g. "john@doc.acme.ac.uk".

   The RFC 822 standard is probably the most widely used on the
   Internet.  X.400 was once used in Europe and Canada.
   UUCP-style (bang path) addresses or other kinds of source
   route became virtually extinct in the 1990s.

   In the example above, "john" is the local part which is the
   name of a mailbox on the destination computer.  If the
   sender and recipient use the same computer, or the same LAN,
   for electronic mail then the local part is usually all that is
   required.

   If they use different computers, e.g. they work at different
   companies or use different Internet service providers, then
   the "host part", e.g. "sales.acme.com" must be appended after
   an "@".  This usually takes the form of a fully qualified
   domain name or, within a large organisation, it may be just
   the hostname part, e.g. "sales".  The destination computer
   named by the host part is usually a server of some kind
   rather than an individual's workstation or PC.  The user's
   mail is stored on the server and read later via client mail
   software running on the user's computer.

   Large organisations, such as universities will often set up a
   global alias directory which maps a simple user name such as
   "jsmith" to an address which contains more information such as
   "jsmith@london.bigcomp.co.uk".  This hides the detailed
   knowledge of where the message will be delivered from the
   sender, making it much easier to redirect mail if a user
   leaves or moves to a different department for example.

   (2014-10-07)