Egypt is from Greek and definitely doesn't mean that. The Egyptian endonym was kmt (traditionally pronounced as kemet), which is interpreted as "black land" (km means "black", -t is a nominal suffix, so it might be translated as black-ness, not at all "quite literally land of the blacks"), most likely referring to the fertile black soil around the Nile river. Trying to interpret that as "land of the blacks" should be suspicious already due to the fact people would hardly name themselves after their most ordinary physical characteristic; the Egyptians might call themselves black only if they were surrounded by non-black people and could view that as their own special characteristic, but they certainly neighboured and had contact with black peoples. And either way one has to wonder if the ancient views of white and black skin were meaningfully comparable to modern western ones. On the other hand, the fertile black soil most certainly is a differentia specifica of the settled Egyptian land that is surrounded by a desert.