The English name for one of the oldest countries on Earth was never used by the people who lived there. It began as the name of a single building.
That building stood at Memphis, the old capital at the entrance to the Nile valley, near Giza. It was the temple of Ptah, a creator god and the city's patron deity. In Egyptian it was Hwt-ka-Ptah, "the house of the ka of Ptah," the ka being a spirit or life force.
Etymonline notes the form Hikuptah in the Amarna period, the 14th century BC. Strictly, it was one of the names of Memphis. Greek speakers turned it into Aigyptos and used it for the river Nile and for the whole country.
The Egyptians had their own name. They called the land Kemet, "the black land," which World History Encyclopedia ties to the rich, dark soil along the Nile. Today the Arabic name is Misr, which Etymonline links to Mizraim, a son of Ham in the Bible.
The Greek word took the long road into English: Latin Aegyptus, Old French Egipte, then Old English, where Egipte first meant "the Egyptians" rather than the place.
Two odd descendants show how far the temple name traveled. Arabic quft is of uncertain origin, but Etymonline says it probably comes from Coptic gyptios, from Greek Aigyptios, "Egyptian." It became Modern Latin Coptus and, in the 1610s, English Copt, the name for Egypt's native Christians.
The other is gypsy. Around 1600 it appeared as an alteration of gypcian, a worn-down Middle English dialect form of "Egyptian." The name reflected a supposed Egyptian origin for the Romani people. However shaky that belief, the word still carries a trace of Ptah's temple.