Dollar sign
The dollar sign is a symbol primarily used to indicate a unit of currency.
The dollar symbol is the only currency mark defined in the 7-bit ASCII computer character set. Other character sets like Unicode contain other currency signs in addition to the dollar.
History
The sign is attested in business correspondence between British North America and Mexico in the 1770s as referring to the Spanish-Mexican piastre. The piastre was known as "Spanish dollar" in British North America, and in 1785, it was adopted as U.S. currency, together with both the term "dollar" and the $ sign.
The sign's ultimate origins are not certain. The most widely accepted explanation, according to the U.S. Bureau of Engraving and Printing, is that "$" is a corruption of the letters "PS" or "Ps" (for 'peso' or 'piastre' - especially the former, as each letter could represent each syllable of "Pé-So") written over each other in Spanish. Eventually, the 'P' was reduced to a vertical line.
Another possibility is that it derives from the British notation 8/ for eight shilling, referring to the Spanish 8 reales coin ("piece of eight"), which later became the USA dollar. Others derive it from the Portuguese Cifrão sign .
Earliest usage wrote the sign with a single vertical stroke. For some time, the double-stroke symbol was common, but is now again falling out of use.
Alternative origin theories
There are a number of alternative origin theories, widely regarded as false, sometimes bordering on the occult.
From a symbol used on the Roman sestertius
That the dollar sign harks back to the most important Roman coin, the Sestertius, which had the letters 'HS' as its currency sign. When superimposed, these letters form a dollar sign with two vertical strokes (the horizontal line of the 'H' merging into the 'S'). This theory is widely discarded, in spite of the tendency of the early US to style itself after the Roman Republic (Capitol, Senate etc.)
From 'US'
That $ is derived from a symbol of U superimposed on S, which was used as a mark on money bags issued by the United States Mint. The letters U and S superimposed resemble the historical double stroke "$" sign: the bottom of the 'U' disappears into the bottom curve of the 'S', leaving two vertical lines. This double stroke dollar sign has been used to refer to US Currency. Thus, the one stroke design may have been modified to the double stroke design to represent United States currency.
The 2 pillars in the temple of Solomon
That the two vertical lines represent the two cult pillars Boaz and Jachin in the original Temple of Solomon at Jerusalem. This is based on the theory that Masonic symbols, such as the All Seeing Eye of God, appear on U.S. currency, which they did not in 1785.
The 2 Pillars of Hercules, plus the 2 hemispheres of the Earth
That the 'S' represents the two hemispheres of the Earth and the || represent the Pillars of Hercules. (This theory is in a Danish book about the $ sign[citation needed].) In 1492 King Ferdinand II of Aragon put Gibraltar under the new joined rule of the Spanish throne, he adopted the symbol of the Pillars of Hercules and added the Latin phrase Nec plus ultra – meaning "and nothing further", indicating "[this is] the end of the (known) world". But as Christopher Columbus later in 1492 travelled to The Americas, the saying was changed to Plus Ultra – as there was more out there. This symbol was especially adopted by Charles V and was a part of his coat of arms as a symbol of his American possessions and riches. When the Spanish conquistadors found gold and silver in the New World, Charles V's symbol was stamped on the coins made from these metals. These coins with the Pillars of Hercules over two hemispheres (columnarios) were spread around America and Europe, and the symbol was ultimately adopted by the country that became the United States and by many of the continent's other independent nations. Later on, salesmen wrote signs that, instead of saying dollar, had this handwritten symbol, and in turn this developed to the simple S with two vertical bars.
From a sign used on the German Thaler
That it derives from the symbol used on a German Thaler. According to Ovason (2004), on one type of thaler, one side showed the crucified Christ, and the other side showed a serpent hanging from a cross, and near the serpent's head the letters NU, and on the other side of the cross the number 21. This refers to the Bible, Numbers, chapter 21.
Use on computers
As the dollar sign is one of the few symbols that is on the one hand almost universially present in computer character sets, but on the other hand rarely needed in its literal meaning within programming languages, the $ character has been used on computers for many purposes not related to money, including:
- $ was used to define string variables in older versions of the BASIC programming language ("$" was often pronounced "string" instead of "dollar" in this use).
- $ is used to define hexadecimal constants in Pascal-like languages as Delphi.
- $ is used to define variables in the Perl and PHP programming languages, and in most Shell scripting languages.
- In UNIX-like systems the $ is often part of the command prompt, depending on the user's shell. The bash shell, for example, uses $ as part of the command prompt.
- $ matches the end of a line in a traditional UNIX regular expression.
- $ is used in the TeX typesetting language to delimit mathematical regions.
Currencies that are not called "dollar" but use the dollar sign
In addition to those countries of the world that use dollars, a number of other countries use the symbol $ to denote their currencies, including:-
- Argentine peso
- Brazilian real
- Bolivian boliviano
- Cape Verde escudo
- Chilean peso
- Colombian peso
- Cuban peso
- Dominican peso
- Mexican peso
- Portuguese escudo (defunct)
- Tongan pa'anga
- Uruguayan peso
References
- Cajori, Florian (1993). A History of Mathematical Notations. New York: Dover (reprint). ISBN 0486677664. - contains section on the history of the dollar sign, with much documentary evidence supporting the "pesos" theory.
- David Ovason, The Secret Symbols of the Dollar Bill (2004) ISBN 0060530456