That little “a” with a circle curling around it that is found in email addresses is most commonly referred to as the “at” symbol.
Surprisingly though， there is no official， universal name for this sign. There are dozens of strange terms to describe the @ symbol.
Before it became the standard symbol for electronic mail， the @ symbol was used to represent the cost or weight of something. For instance， if you purchased 6 apples， you might write it as 6 apples @ $1.10 each.
With the introduction of e-mail came the popularity of the @ symbol.The @ symbol or the “at sign” separates a person's online user name from his mail server address.For instance， . Its widespread use on the Internet made it necessary to put this symbol on keyboards in other countries that have never seen or used the symbol before. As a result， there is really no official name for this symbol.
The actual origin of the @ symbol remains an enigma.