Pieces of eight is a term that refers to a Spanish coin that was used as currency in the 16th and 17th centuries. It was called so because it was divided into eight pieces or reales. The term has been popularized in various works of fiction, including pirate stories and adventure novels. However, there are several synonyms for "pieces of eight" that can be used interchangeably. These include "Spanish dollar," "peso," "tael," and "thaler." In modern usage, the phrase "pieces of eight" has come to represent activities related to treasure hunting and pirate lore, making it a popular phrase in pop culture.