Messiah is a word that is bound up with "Anointed One," and in the Old Testament the king was anointed, and the priests were anointed as they were appointed to their particular roles, and on one or two occasions a prophet was anointed, like Elisha. And so it came to be associated with expectation of one who was to come, but most commonly with kingdom and namely with the Davidic kingdom. But you have to recognize that Jews were divided on such matters. In Qumran, for example, in the area near the Dead Sea south of Jerusalem, it's pretty clear that they expected two Messiahs: a priestly Messiah and a kingly Messiah. And what Christ does when he comes along, turns out to be king and priest. In one sense, they were right, but they wanted two figures, and we have one figure being both priest and king, and prophet too for that matter as well. So, there was rising expectation of one who was to come, and as far as I can see, when Messiah is connected with a coming one, most likely it's the Davidic figure who is in view, that is, the promised king in the Davidic line with prophecies going back finally to the seedbed of 2 Samuel chapter 7 and reinforced by a typological reading of Psalm 2 and Psalm 110 and so forth. So, when we come to the word "Christ," which is simply the Greek equivalent of Messiah, when it has titular force, and I think it never loses all of its titular force in the New Testament. It's regularly a way of saying that Jesus is the Davidic king, though in the right context it might have other overtones of priesthood and authority beyond that.