Cleo is a diminutive of Cleopatra, used both as a feminine and masculine given names. Cleopatra originates in Greek language and means "father's glory". Cleopatra is the name of several pharaohs in Ancient Egypt. The most famous and depicted one was Cleopatra VII, the last pharaoh in Ancient Egypt, wife of Julius Caesar and Mark Antony. Probably because the name is so closely connected to this historical personality, it has never been overly popular as a feminine given name in the United States.