At sign (@): what it is, what it does in email and how to type it
From a unit of weight to an internet symbol
The at sign (@) 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.
Today it is also used on social media to mention other people. But its history begins long before the internet, in merchants’ account books.
What is the at sign for in an email address?
Every email address has three parts:
- The username, which identifies the person or the mailbox (for example, “laura” or “sales”).
- The at sign (@), which marks where the username ends and the domain begins.
- The domain, which indicates the server that receives the email (for example, “empresa.es”).
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.
Create your free email marketing account
Import your contacts and send your first newsletter today, with up to 80,000 emails a month for free.
Where does the at sign come from?
The Spanish word “arroba” comes from the Arabic ar-rub’, “one quarter”. In Castile, the arroba was a unit of weight 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.
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.
The big leap came in 1971. Engineer Ray Tomlinson sent the first email between two computers on ARPANET, 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.
How do you type the at sign on the keyboard?
It depends on the system and the keyboard layout:
| Device | Spanish keyboard (Spain) | Other keyboards |
|---|---|---|
| Windows | AltGr + 2 | Alt + 64 on the numeric keypad (works on any layout); Latin American: AltGr + Q |
| Mac | Option (⌥) + 2 | English: Shift + 2 |
| Linux | AltGr + 2 | Latin American: AltGr + Q |
| Mobile (Android or iPhone) | Symbols key (?123) | In email fields, the @ appears directly |
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 @.
Besides email, the at sign has other common uses:
- Social media mentions. On X, Instagram or TikTok, an @ in front of a name tags that account and sends it a notification. Not to be confused with the hashtag (#), which groups topics.
- Inclusive language. Forms like “tod@s” are seen sometimes, but the RAE does not accept them: the at sign is not a letter and cannot be read aloud.
- Names in other languages. In English it is read “at”; in Italian, “chiocciola” (snail); in German, “Klammeraffe” (clinging monkey); and in Swedish, “snabel-a” (a with a trunk).
How Mailrelay helps you
Behind every at sign there is a person you can write to. With Mailrelay you import your contacts from a CSV or Excel file, organize them into groups and send them newsletters, campaigns and automations from the same dashboard.
To make sure your emails get delivered, it is best to send from an address on your own domain, such as a corporate email, and to set up your sending domain. With the free account you can send up to 80,000 emails per month.
Start for free with Mailrelay
Newsletters, campaigns and automations from a single dashboard, with human support.
Frequently asked questions
What does the at sign mean in an email?
It separates the username from the domain. It can be read as “at”: the user “laura” at the domain “empresa.es”.
How do you type the at sign on a computer keyboard?
On a Spanish keyboard, with AltGr + 2 on Windows and Linux, and with Option + 2 on Mac. On Windows, Alt + 64 on the numeric keypad also works.
Why is it called “arroba” in Spanish?
Because that was the name of an old unit of weight of about 11.5 kg, which merchants abbreviated with the @ symbol. The name comes from Arabic and means “one quarter”.
Who chose the at sign for email?
Ray Tomlinson, the engineer who sent the first email between computers in 1971.
Can an email address have two at signs?
No. A valid address has only one at sign, which separates the username from the domain.