The wor peso (meaning weight in Spanish) was the name of a coin that originated in Spain and became of immense importance internationally. Peso is now the name of the monetary unit of several former Spanish colonies. This article gives a brief summary of the origin and evolution of the peso coin, which was the basic silver coin of Spanish America from the 15th through the 19th centuries (see: Currency of Spanish America). This coin was originally known in English as a piece of eight, then as a Spanish dollar, and then as a Mexican dollar. This peso coin was called piastre in French and pataca or patacão in Portuguese. In Spanish, this peso was also known at various times and in various places as a patacón, a duro, or a fuerte.