The term 'Old Spanish Gold Coin' can be summarized as a DOUBLOON, which is an 8-letter word. A DOUBLOON was a type of gold coin used by the Spanish Empire from the 16th to 19th centuries. It was widely used in Europe and the Americas during the period of exploration and colonization. The coins were made of gold and were often stamped with the Spanish coat of arms. They were also used as a form of currency in many parts of the world.