I've just been referring to all of them as nickel, since I don't think I've seen one time yet when we haven't had two guys lined up at "linebacker" positions. If we ever move Roy out of the box and play him deep, with one linebacker and four linemen, I'll call it a dime. But to me, when he's in the box with a four-man line, two corners, two deep safeties and a third corner in the slot, he's playing nickel linebacker, not dime safety. To me, it's more about the formation than the personnel.
Whether the team uses different terms to signify different personnel packages is another matter. But Wade has talked plenty about using Roy as a "nickel linebacker," so maybe he's not even sure what to call it.