The symbol $, usually written before the numerical amount, is used for the U.S. dollar (as well as for many other currencies). The sign was the result of a late 18th-century evolution of the scribal abbreviation "ps" for the peso, the common name for the Spanish dollars that were in wide circulation in the New World from the 16th to the 19th centuries. These Spanish pesos or dollars were minted in Spanish America, namely in Mexico City, Potosi, Bolivia; and Lima, Peru. The p and the s eventually came to be written over each other giving rise to $.
Is there an answer to this question (If it cannot be answered, say "unanswerable"): What was the common name for the Spanish dollar?
peso