There is limited proof that the currency symbol used for the U.S. dollar grew out of an abbreviation for Spanish Pesos (SP), but it is the most widely accepted theory.
The symbol used to denote the ($) United States dollar, Canadian dollar, Mexican peso, and more is a capital S crossed with one or two vertical strokes.
Theories About the Dollar Symbol
A study of 18th and 19th-century manuscripts suggests American and Spanish scribes abbreviated ps for Spanish Pesos and, over time, that the S came to be written over the P, resulting in $. The Spanish milled dollar or peso was so commonly used in the United States that early colonial dollars were denominated as such. Early U.S. dollars borrowed their name and weight from the Spanish dollar.
Today, many nations use the dollar sign, although it is known to many people as the peso sign, and some nations refer to it as a cifrão.
Background of the Dollar Symbol
Oliver Pollock, an Irish trader who moved to the United States, used the SP abbreviation with the s and p connected to form a shape that resembles the current dollar symbol, and that use is documented as early as 1778.
Some historians point to Pollack as the creator of the dollar symbol, and others point to his poor penmanship, which he was well known for.
Earlier Portuguese documents show a two-stroke version of the dollar symbol used in 1775.
Why did the Dollar Sign Have Two Lines?
One theory supposes that the sign represents the Pillars of Hercules, a symbol for the Straight of Gibraltar’s sides with a ribbon wrapped around them in an S shape. This symbol is present on the Spanish coat of arms and was featured on Spanish coins like the reales that heavily circulated the American colonies.
Amidst the litany of theories, one proposed by author Ayn Rand (Atlas Shrugged) suggested that the dollar symbol was formed by writing the letters U.S. in a creative fashion. In Rand’s theory, the bottom of the U was eliminated, leaving an S with two vertical strokes, which became an S with a single stroke over time.
Other Nations That Use the Dollar Symbol
There are a multitude of nations that use the dollar sign to denote their currency. In Brazil, Portugal, and other nations that were part of the Portuguese Empire, the dollar sign is used explicitly with two strokes and called the cifrão.
Nations Using the Dollar Sign
It is worth noting that most of these nations simply use the $ when referring to the local currency for domestic use.
| Nation | Currency | Denoted as | Code |
| United States | United States dollar | US$ | USD |
| Canada | Canadian dollar | CA$, Can$, C$ | CAD |
| Australia | Australian dollar | A$, AU$ | AUD |
| New Zealand | New Zealand dollar | NZ$ | NZD |
| Hong Kong | Hong Kong dollar | HK$ | HKD |
| Brazil | Brazilian real | R$ | BRL |
| Mexico | Mexican peso | MX$, Mex$ | MXN |
| Macau | Macanese pataca | MOP$ | MOP |
| Argentina | Argentine peso | $ | ARS |
| Barbados | Barbados dollar | Bds$ | BBD |
| Bahamas | Bahamian dollar | B$ | BSD |
| Bermuda | Bermudian dollar | BD$ | BMD |
| Cayman Islands | Cayman Islands dollar | CI$ | KYD |
| Chile | Chilean peso | CLP$ | CLP |
| Colombia | Columbian peso | COL$ | COP |
| Fiji | Fijian dollar | FJ$ | FJD |
| Liberia | Liberian dollar | $ | LRD |
| Namibia | Namibian dollar | $ | NAD |
| Singapore | Singapore dollar | S$ | SGD |
| Nicaragua | Nicaraguan córdoba | C$ | NIO |
| Samoa | Samoan tālā | WS$ | WST |
| Tonga | Tongan pa’anga | T$ | TOP |
