Pieces of eight is a term that originated in the 16th century and was used to refer to Spanish dollars or 8-real coins. The term is also used to refer to a specific type of pirate treasure, which is why it is often seen in crosswords. The solutions to this crossword are QUARTETS (8 letters), octets (6 letters), PESOS (5 letters), fours (5 letters), and octads (6 letters). QUARTETS and octets refer to groups of four and eight respectively, while PESOS, fours, and octads all refer to monetary units.