「@」符号（半角文本表示：@,U+0040，全角文本表示：＠），是英文单词“at”或英文短语“at the rate of”的缩写，表示“在”、“以某一速率或比率”等意思。它是一现在常见的符号，因为在电子邮件地址中，它是用户名和邮件服务器的域名之间的分隔符。此外，「」符号也被用作斯沃琪互联网时间（Swatch Internet Time）的前置符号，代表的是目前以「拍」（.Beat）做单位的时间。 “@”符号在Twitter、新浪微博等微博客网站、Youtube评论等地方也会使用到。例如，在Twitter中，在 @ 符号后边紧跟一个用户名可以让用户直接给对方发送信息。例如，一条包含有@example的消息可以直接送达对方，并且在“Reply”中显示，同时，别人也能看到这条消息。

The at sign, @, normally read aloud as "at", also commonly called the at symbol or commercial at, is originally an accounting and commercial invoice abbreviation meaning "at a rate of" (e.g. 7 widgets @ £2 = £14). In contemporary use, the at-sign is most commonly used in email addresses. It was not included on the keyboard of the earliest commercially successful typewriters, but was on at least one 1889 model and the very successful Underwood models from the "Underwood No. 5" in 1900 onward. It is now universally included on computer keyboards. The mark is encoded at U+0040@COMMERCIAL AT (HTML @).