{"id":85687,"date":"2025-07-17T14:19:09","date_gmt":"2025-07-17T14:19:09","guid":{"rendered":"https:\/\/mailrelay.com\/glossary\/at-sign\/"},"modified":"2026-10-19T12:49:25","modified_gmt":"2026-10-19T12:49:25","slug":"at-sign","status":"publish","type":"glossary","link":"https:\/\/mailrelay.com\/en\/glossary\/at-sign\/","title":{"rendered":"At sign"},"content":{"rendered":"\n

The at sign (@)<\/strong> is the symbol that separates the username from the domain in an email address. It is read as “arroba” in Spanish and “at” in English: an email address literally means “this user at this domain”. Without it, email as we know it would not exist.<\/p>\n\n

Today it is also used on social media to mention other people. But its history begins long before the internet, in merchants’ account books.<\/p>\n\n

What is the at sign for in an email address?<\/h2>\n\n

Every email address<\/a> has three parts:<\/p>\n\n

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  1. The username<\/strong>, which identifies the person or the mailbox (for example, “laura” or “sales”).<\/li>\n\n\n\n
  2. The at sign (@)<\/strong>, which marks where the username ends and the domain begins.<\/li>\n\n\n\n
  3. The domain<\/strong>, which indicates the server that receives the email (for example, “empresa.es”).<\/li>\n<\/ol>\n\n

    Thanks to the at sign, servers know who to deliver each message to and which domain to look it up in. That is why an address can only have one @, and it does not allow spaces.<\/p>\n\n

    \"Infographic<\/figure>\n\n
    \n

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    Create a free account<\/a><\/div>\n<\/div>\n<\/div><\/div>\n\n

    Where does the at sign come from?<\/h2>\n\n

    The Spanish word “arroba” comes from the Arabic ar-rub’<\/em>, “one quarter”. In Castile, the arroba was a unit of weight<\/strong> of 25 pounds, about 11.5 kg, and also a unit of volume for wine or oil. That is why “weight symbol in email addresses” is a classic crossword clue.<\/p>\n\n

    The @ symbol already appeared in commercial documents in the 15th century. One of the oldest known in Spain is an Aragonese table from 1448, where it is used to measure wheat. In Italy, a Florentine merchant used it in 1536 to count amphorae of wine.<\/p>\n\n

    The big leap came in 1971. Engineer Ray Tomlinson sent the first email between two computers on ARPANET<\/a>, the network that gave rise to the internet. He needed a sign that did not appear in usernames and was already on the keyboard, and he chose the @. In 2010, the MoMA in New York added the symbol to its design collection.<\/p>\n\n

    How do you type the at sign on the keyboard?<\/h2>\n\n

    It depends on the system and the keyboard layout:<\/p>\n\n

    Device<\/th>Spanish keyboard (Spain)<\/th>Other keyboards<\/th><\/tr><\/thead>
    Windows<\/td>AltGr + 2<\/td>Alt + 64 on the numeric keypad (works on any layout); Latin American: AltGr + Q<\/td><\/tr>
    Mac<\/td>Option (\u2325) + 2<\/td>English: Shift + 2<\/td><\/tr>
    Linux<\/td>AltGr + 2<\/td>Latin American: AltGr + Q<\/td><\/tr>
    Mobile (Android or iPhone)<\/td>Symbols key (?123)<\/td>In email fields, the @ appears directly<\/td><\/tr><\/tbody><\/table><\/figure>\n\n

    If a combination does not work, check which keyboard language is active. On a website, the at sign can also be written with the HTML code @<\/code>.<\/p>\n\n

    \"How<\/figure>\n\n

    The at sign on social media and in other uses<\/h2>\n\n

    Besides email, the at sign has other common uses:<\/p>\n\n