I cite Ephraem the Syrian because we have negative neybobs on these threads that insist the notion of Rapture is a nineteenth century creation. It is not. It can be found in many Historiacal documents/discussions dating even to 100 AD.
Neybobs they are. But the issue, to pre, mid, and post tribbers, is not whether there is going to be a rapture, but when does it take place.
I don't think that's it so much as dispensationalists mean something different by 'rapture' than the rest of us do. For example, to Catholics, 'rapture' is most often taken to mean "prophecy that takes place while the senses are suspended in ecstasy" (New Advent encyclopedia).
Ben Witherington explains it in a couple of Seven Minute Seminary segments on Seedbed.