When was Egypt known as ancient Egypt?

Answer 1

The word comes from the ancient Greek version of the local name - the Greeks called it Aigyptos which English speakers much later anglicised to Egypt.

Answer 2

The formal United Kingdom of Egypt was created in 3150 BC by King Menes. This is about the time when historians refer to Egypt as ancient Egypt. However, during 2700-2200 BC, the Old Kingdom period is the first notable ancient Egyptian dynasty when man pyramids were built.