Why a forgotten printing symbol became the cornerstone of email addresses
In 1971, computer engineer Ray Tomlinson was looking for a way to route messages between different computers on the ARPANET. He needed a character to separate the user's name from their host computer, choosing the "@" symbol because it was rarely used in programming and meant "at." This simple choice saved the obscure ledger symbol from obscurity, turning it into a global icon.
The Commercial Shorthand of Merchants
Before it became synonymous with digital communication, the "@" symbol lived a quiet life in ledgers, invoices, and trade documents. Known in English as the commercial "at" or "at sign," its primary historical role was as an accounting abbreviation meaning "at the rate of." A grocer or merchant recording a transaction would write an entry such as "6 apples @ $1" to indicate that six items were being purchased at a unit price of one dollar each, totaling six dollars. This shorthand saved ledger space and reduced repetitive handwriting in high-volume trade environments.
The exact historical emergence of the glyph remains a subject of paleographic study, with several complementary lineages. One prominent theory traces the symbol to medieval Latin scribes, who routinely merged the two letters of the preposition "ad"—meaning "at," "to," or "toward"—into a single ligature to save parchment and stroke time. Another documented branch comes from Mediterranean trade: in 14th- and 16th-century commercial documents from Spain, Portugal, and Italy, similar marks represented the "arroba," an ancient unit of weight and volume roughly equivalent to 25 pounds, which itself derived from the Arabic term "al-rub'" (meaning a fourth). By the time modern commerce industrialized, the mark was firmly entrenched across bookkeeping traditions as a utility sign for pricing and quantities.
The Mechanical Route to the Digital Age
The transition of the symbol from hand-drawn accounting shorthand to standardized typography began with the mechanical typewriter. In the late 19th century, typewriter manufacturers aimed their machines squarely at business offices, where clerks processed orders, billing statements, and inventories. Machines like the 1880s Underwood typewriter began incorporating the commercial "at" key directly onto the keyboard alongside standard numerical digits, fractions, and currency symbols like the dollar sign.
Because of its presence on physical business equipment, the symbol naturally migrated into electronic telecommunication standards. When character sets were formalized for early computing and teleprinters in the mid-20th century, the American Standard Code for Information Interchange (ASCII) established a common numeric encoding for text. Ratified in 1963, ASCII assigned the "@" symbol character code 64 (octal 100). This ensured that standard terminal keyboards, such as the widely used Teletype Model 33, featured the character as an accessible, hardware-level standard, even though computer programs of the era rarely made use of it.
Ray Tomlinson's ARPANET Dilemma
In 1971, computer engineer Ray Tomlinson was working for Bolt Beranek and Newman (BBN), a research and development company heavily involved in building the ARPANET—the packet-switching network funded by the U.S. Department of Defense that preceded the modern internet. At the time, primitive messaging systems existed, such as the local program SNDMSG, but these utilities only allowed users sharing the exact same physical mainframe computer to leave messages for one another in local mailbox files.
Tomlinson sought to expand messaging across the network by combining SNDMSG with an experimental file-transfer protocol called CPYNET. To make network messaging work, a message's destination address needed two distinct pieces of information: the identifier of the specific recipient and the identifier of the remote computer where that recipient held an account. The mechanical challenge was finding a delimiter—a single punctuation character—to sit between the user's name and the host machine's name without confusing the computer's parsing software.
The separator needed to satisfy a strict requirement: it could not be a character that people already used in their login usernames or personal names, which ruled out letters, numbers, spaces, periods, and hyphens. Tomlinson looked down at his Model 33 Teletype keyboard and spotted the rarely touched commercial "at" key. It was an ideal technical solution because it was almost completely unused in standard operating system commands, and linguistically it made intuitive sense in English: a message sent to "user@host" translated naturally to "user at host machine."
Building a Global Addressing Convention
The first networked email Tomlinson sent was an experimental message between two side-by-side computers connected through the ARPANET. While Tomlinson later noted that the exact text of that first test transmission was forgettable—likely a string of random characters like "QWERTYUIOP"—the syntax he invented proved enduring. The "user@host" addressing convention spread rapidly across ARPANET nodes as researchers and institutions adopted network email as their primary communication tool.
As computer networking expanded beyond ARPANET and evolved through various competing network protocols—such as UUCP, BITNET, and CSNET—diverse addressing formats competed for supremacy. Some systems used exclamation marks to indicate "bang paths" (routing hops through specific computers), while others used percent signs or colons. When the Internet Engineering Task Force (IETF) standardized the Domain Name System (DNS) and the Simple Mail Transfer Protocol (SMTP) in the early 1980s, the "@" symbol was codified as the universal separator for email addresses worldwide, permanently cementing Tomlinson's design choice.
Cultural Interpretations Across Languages
Because the commercial "at" symbol was primarily an Anglo-American accounting convention, speakers of other languages did not inherit a native term for the character when email arrived on their screens. Instead of translating the English word "at," diverse linguistic cultures described the unusual looped glyph by its visual appearance, inventing a colorful taxonomy of everyday metaphors.
In Hebrew, the symbol is commonly referred to as a "strudel," referencing the rolled layers of the traditional pastry. Italian speakers call it "chiocciola" (snail), while in French it is formally known as "arobase" but colloquially described as "escargot." In German, it became "Klammeraffe" (spider monkey or clinging monkey), and Dutch adopted "apenstaartje" (little monkey's tail). In Danish and Swedish, it is designated "snabel-a" (an 'a' with an elephant's trunk), while Russian speakers refer to it as "sobaka" (dog), and Hungarian uses "kukac" (worm or maggot). These divergent terms highlight how a purely functional technological tool was integrated into global vocabularies through visual analogy.
The Evolution from Utility to Cultural Icon
Over subsequent decades, the utility of the "@" symbol expanded well beyond the basic routing of email headers. Computer programming languages adopted it for specialized technical operations: Perl used it to denote array variables, Python utilized it to mark function decorators, and other languages employed it for string literals or error suppression. Its structural role remained consistent—a compact syntactic marker that computers could distinguish instantly from regular text.
In the 21st century, social networking platforms transformed the symbol once again by repurposing it for public digital interaction. Systems like Twitter (now X), Instagram, and collaboration platforms introduced "@mentions" and handle identifiers, turning the symbol into an active prefix for directing attention, tagging participants, and asserting personal digital identity.
The symbol's trajectory from an obscure accounting notation to one of the most recognizable graphic marks in human history was formally acknowledged in 2010, when the Museum of Modern Art (MoMA) in New York acquired the "@" symbol for its Department of Architecture and Design collection. MoMA noted that while the physical design of the character had roots centuries old, its modern adaptation by Ray Tomlinson represented an extraordinary piece of invisible, functional design that reshaped global human communication.
Key takeaways
•Before digital computing, the '@' symbol was an accounting shorthand meaning 'at the rate of,' with historical roots in medieval scribal ligatures and Mediterranean trade records.
•Ray Tomlinson selected '@' in 1971 while developing ARPANET email because it was available on his Teletype keyboard, was not used in usernames, and intuitively conveyed 'user at host.'
•Because the symbol lacked a direct equivalent in many non-English languages, cultures around the world named it after visual metaphors, including snails, monkey tails, strudels, and elephant trunks.
•The symbol transitioned from a basic email routing separator into a universal standard for social media tagging, programming syntax, and modern digital identity.