The Greek words are the same as in Matthew 24, but obviously, the great tribulation suffered by Egypt in Joseph's time is not at all the same as the future Tribulation that Christ mentions in Matthew 24. The use of identical language is, of course, not accidental and begs our attention.
Stephen says that Egypt and Canaan suffered greatly from two things: first, from "famine," and second, from "great trouble." The sense of the Greek is that the famine, the lack of food, caused the great trouble that Stephen speaks of here. The tribulation does not stand alone. J.B. Phillips translates Stephen's statement as, "Then came the famine over all the land of Egypt and Canaan which caused great suffering."
The tribulation of which Stephen speaks went beyond the famine itself. After all, the people, because of Joseph's planning, did have access to some food. Apparently, there was not mass starvation at this time in Egypt. What form did this famine-induced great tribulation take in Egypt? Today, we would say that the famine caused economic, social, and political upheaval. "Upheaval" is a slightly weak word—in fact, the word "revolution" is more accurate.
The Other Great Tribulation