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

commercial at
@
at sign

    "@".  ASCII code 64.  Common names: at sign, at,
   strudel.  Rare: each, vortex, whorl, INTERCAL: whirlpool,
   cyclone, snail, ape, cat, rose, cabbage, amphora.  ITU-T:
   commercial at.

   The @ sign is used in an electronic mail address to separate
   the local part from the hostname.  This dates back to July
   1972 when Ray Tomlinson was designing the first[?] e-mail
   program.

   It is ironic that @ has become a trendy mark of Internet
   awareness since it is a very old symbol, derived from the
   latin preposition "ad" (at).

   Giorgio Stabile, a professor of history in Rome, has traced
   the symbol back to the Italian Renaissance in a Roman
   mercantile document signed by Francesco Lapi on 1536-05-04.

   In Dutch it is called "apestaartje" (little ape-tail), in
   German "affenschwanz" (ape tail).  The French name is
   "arobase".  In Spain and Portugal it denotes a weight of about
   25 pounds, the weight and the symbol are called "arroba".
   Italians call it "chiocciola" (snail).

   See @-party.

   (2003-04-28)