Many of the most common symbols on our keyboards have fascinating origin stories. Some, such as the zero, we now take for granted—yet the idea of denoting an absence of value was not present in Western mathematics until introduced from the East. Other symbols, such as the hashtag or at-sign, had a variety of uses until the internet ushered in a new way of communicating and fixed them with the meanings we know today. Below are six examples of the first known usage and subsequent history of some of the most common typographic symbols.
1. AT SIGN // @
The @ (or at-sign) is usually dated to 1536 in a letter from a Florentine merchant, Francesco Lapi, who used it to mean a unit of wine called “amphorae.” But a Spanish researcher claims to have found an even earlier usage in a 1448 document, where the symbol also referred to a unit of measurement (even today, Spaniards call the @ symbol arroba, which is also a unit of weight, and some other Romance languages have similar dual meanings). Either way, the researchers think that the symbol then moved to Northern Europe, where it eventually gained the meaning of “at the price.” Other explanations have also been offered, but whatever the exact root of the symbol, its meaning eventually became known as shorthand for at, and it was generally used in written financial transactions—for example, in noting “Bob sells James 4 apples @ $1.”
The sign had largely fallen out of use by the early 1970s, when computer scientist Ray Tomlinson was working at what is now BBN Technologies, in Cambridge, Massachusetts. Tomlinson, who was working for the government on a forerunner of the internet, was trying to figure out how to address messages sent from one computer to another when he noticed the little-used @ on his computer keyboard, and used it to send a prototype email. This precedent was soon adopted as the internet developed, and the at-sign is now, of course, central to our lives.
2. ZERO // 0
The absence of a value is a complex concept, one that many ancient civilizations struggled with. The idea of a zero ultimately came to the West from the mathematicians of India, where, as in a few other cultures, zero was initially used as a placeholder, for example to indicate a lack of units, as in the number 101.
The earliest surviving usage of a zero in India has been traced to an ancient mathematical text known as the Bakhshali manuscript, which is held at Oxford’s Bodleian Library. In September 2017, radiocarbon dating indicated that the manuscript was produced as early as the 3rd or 4th century—providing us with the first known usage of zero some 500 years earlier than previously thought. As Oxford’s Bodleian Library says, “the symbol in the Bakhshali manuscript is particularly significant for two reasons. Firstly, it is this dot that evolved to have a hollow centre and became the symbol that we use as zero today. Secondly, it was only in India that this zero developed into a number in its own right, hence creating the concept and the number zero that we understand today."
The manuscript itself was discovered buried in a field in 1881 in what is today Pakistan. Written on 70 delicate leaves of birch bark, historians think it represents a training manual for Silk Road traders, teaching them concepts of arithmetic.
3. HASHTAG // #
The origin of the hashtag (or pound sign as it's traditionally known in the U.S.) comes from scribes writing shorthand for the Latin libra pondo, which translates as "pound by weight." The abbreviation they used was lb, which was sometimes misread as 16. So, scribes took to drawing a line through the top of the two letters, which over time developed into the now familiar #. In the 1960s, the pound sign was chosen by Bell Laboratories to be a function key on their newly designed telephone keypad. (The Bell Labs team fondly nicknamed the symbol the “octothorpe,” possibly in honor of athlete Jim Thorpe.) Fast-forward to 2007, when early Twitter users wanted to be able to group and filter their feeds, so developer Chris Messina suggested they appropriate the method used in IRC (Internet Relay Chat) whereby users employed the pound sign or "hashtag" to signpost what they were chatting about. (Programmers knew the symbol as the hash, which was now being used to "tag" content.) This simple method soon caught on, and today the hashtag has become indelibly linked to the rise of social media.
4. ELLIPSIS // …
Originally, periods of silence were marked textually with a series of hyphens, but today the symbol of choice is the …, a.k.a. the ellipsis. Dr. Anne Toner of Cambridge University spent years researching the ellipsis and finally discovered what she thinks is its first use—an English translation of Roman dramatist Terence’s play Andria printed in 1588. Although the play used hyphens instead of dots, the general idea caught on rapidly. (Toner notes that although there are only four “ellipses” in the 1588 translation, there are 29 in the 1627 version.) By the 18th century, dots started to replace the dashes, which an assistant professor from Southeastern University suggests may be connected to a medieval piece of punctuation called subpuncting or underdotting, which generally indicated something was incorrectly copied.
5. AMPERSAND // &
The ampersand originated in Latin when the word et (meaning and) was written in cursive script as a ligature (in which one or more letters are written together as a single glyph). One of the earliest examples was found daubed in graffiti on the walls of a house in Pompeii, where it was preserved by the eruption of Vesuvius in 79 CE. By the 8th century the ampersand became a recognizably distinct character, but the word ampersand did not come into use until the late 18th/19th century, when English school children would recite "and per se and" meaning “and by itself means and” to help remember the symbol (per se being Latin for "by itself"). One of the most thorough investigations into the typographic history of the ampersand comes courtesy of German graphic designer Jan Tschichold, who in 1953 published The ampersand: its origin and development, in which he collected numerous examples of the ampersand from the 1st century onwards, visually charting its developing form.
6. PLUS SIGN // +
The plus sign used for addition in mathematics likely derives from a shorthand ligature for the Latin et meaning “and” and was probably in use for a long time before a surviving example appeared in print. One candidate for the earliest surviving usage is in French philosopher and polymath Nicole Oresme's Algorismus proportionum, a manuscript handwritten between 1356 and 1361, although scholars debate whether it's a true plus symbol. The first use of a plus sign in a printed book is more definitive, and can be found in a 1489 edition of Johannes Widmann’s Mercantile Arithmetic. Widmann also uses the minus sign for the first time in print in this volume—although both plus and minus signs relate not to addition and subtraction but to surpluses and deficits in business accounting. After this usage, the plus sign began to appear more frequently in German mathematical texts, and first appeared in an English text in 1557 in Robert Recorde’s The Whetstone of Witte—which also introduced the equals sign.