Capcom has been adamant about the fact that DMC is a re-imagining of their Devil May Cry mythos. That means Dante looks different, drops the F-bomb a whole lot more and adventures through a different landscape, even if the game plays very similarly to the titles of the past.
Why, then, do some of his weapons still have the same names? Why not different names? Heck, why have names at all? Why not just call the axe an axe and the sword a sword? It's a reboot, right?
When I asked this of Capcom producer Motohide Eshiro, he said keeping the pistols' names Ebony and Ivory and giving nomenclature to other weapons in DMC acts a touchstone to the Devil May Cry games that came before. Sure, they're changing a lot of things, he continued, but if they changed decisions like that, then they might as well call the game something else entirely. Dante's sword may be called Rebellion but Capcom's not going to reject everything about the DMCs of the past.