How many countries have the word "Guinea" in their names?

Four countries have Guinea in their names: Guinea, Equatorial Guinea, Guinea-Bissau, Papua New Guinea.

English "Guinea" is derived from the Portuguese word "Guiné" which originated during the mid-15th century. The word Guinea was used to refer to the lands owned by the Guineus, which was a collective term for the African people who came from regions south of the Senegal River.

An alternative theory claims that the term Guinea is derived from Djenné, a city in modern-day Mali that was heavily important in the trans-Saharan trade from the 15th to 17th centuries. The Djenné period of dominance featured the use of the term "Genawah" which is the Arabized word for "Ghinawen", meaning "blacks".