At sign

Epic card · No. 6146

The at sign (@) is a typographical symbol used as an accounting and invoice abbreviation meaning "at a rate of" (e.g. 7 widgets @ £2 per widget = £14), and now seen more widely in email addresses and social media platform handles. Most languages have their own name for the symbol. Although not included on the keyboard layout of the earliest commercially successful typewriters, it was on at least one 1889 model and the very successful Underwood models from the "Underwood No. 5" in 1900 onward. It started to be used in email addresses in the 1970s, and is now routinely included on most types of computer keyboards.

Read on Wikipedia