It is just called the at symbol was my reply.
Afterwards I decided to do some googling and came across this article http://www.worldwidewords.org/articles/whereat.htm.
Michael Quinion writes on International English from a British viewpoint. It would seem that the original symbol was an amphora which was a unit of weight in medieval Italy and @ was a handwritten A embellished in typical Florentine style.
Use of it within internet email addresses has led to the symbol being imported into many different languages. Names mentioned in Quinion's article include
- Klammeraffe (spider monkey in German)
- grisehole (pig's tail in Danish)
- snabel (elephant's tail in Swedish)
- apestaart (monkey's tail in Dutch)
- kukac (worm in Russian)
Michael Quinion's site World Wide Words is an Aladin's cave of articles on all aspects of word usage. This lexicographer and word-lovers' site has been going since 1996 which is an eon in internet time. Now I've discovered it I shall be making regular visits.