ALL OF A SUDDEN, you see that little sign everywhere - on business cards, with bylines in newspapers, in TV. Those who keep up with the information age may know that it is used for e-mail addresses; the code you write when you send an electronic letter from your computer via modem and telephone.

But what is it called, and how did it originate?

In Sweden it is popularly known as "cinnamon bun", "a-hose", "elephant's ear" etc. In France it is called "arobas" (meaning unknown) or "a roulé", in Holland "apestaart" (monkey tail), in Italy "chiocciola" (snail) and in Israel "shtrudel".

In English it is formally called commercial at or at-sign and has been used for a long time in the sense "at a price of ...(each)": "3 barrels @ $200." Eventually it also took on the locative sense of the word "at".

The @-sign is definitely not a child of the computer age - its history goes far back. Berthold Louis Ullman, American professor of Latin and paleography, claims in his book "Ancient Writing and Its Influence" that the at-sign is a ligature, that is, two letters tied together. The Latin preposition "ad", meaning at, to, toward, was simplified into something like the @-sign we know. The bowl of the a and the d merged and the upstroke of the d was exaggerated and curved to the left.

The @-ligature might be as old as from the 6th or 7th century. At that time the scribes used the uncial, a hand with rounded, sometimes simplified capitals, which could be written with fewer pen-strokes. A lot of abbreviations and ligatures were developed, partly for convenience and partly as a necessity, for writing close to the end of a line.

We cannot, however, be sure that the sign is as old as that. Maybe it emerged (or re-emerged) in the Gothic hand of the 12th or 13th century, a time when many old conventions for ligatures and abbreviations were revived.

Through the centuries, the at-sign has been used primarily in clerical writing and business correspondence. It has been used also in Sweden, and was reportedly available on some early Swedish typewriters.

The at-sign was probably adopted into the computer world around 1970 under the operating system Tenex, and used for e-mail on the early Internet as well as for programming.