As far as I know...
Pass - A sleight that quickly switches the top and bottom packets. Essentially a cut that is supposed to go unseen.
Hop - A tabled Pass designed to negate the cut in a card game.
Shift - A more general term. Can be applied to packets like a Pass (SWE Shift) or to the movement of a single card (Diagonal Palm Shift or Clipshift). Currently it seems to apply more to a single card, but originally it was the term for a Pass.