Dec 11, 2019 · In English, the symbol @ had traditionally meant “at” or “at a rate of.” For a long time, it has therefore been used to indicate price per unit in commercial contexts, such as on an invoice. For instance: 5 bottles of wine @ $7 per bottle = $35.

For nearly a century, the symbol was primarily used as shorthand for the phrase "at the rate of," as in the following example: 5 bananas @ .40 cents per pound = .75 cents. Since the 1990s, the symbol has been most widely recognized as the universal "at"-prefix for email accounts.