In German the general term is "Wiedergänger" which is the exact translation of "Revenant" so "one who walks again". Going by the folklore, and as you said, that could be any number of stuff we specifically name today. Aaand I also have the Folklore of Discworld book. It lead me to dig up the entire ballad of Moore of Moore hall and the Dragon of Wantley one day. Good stuff.It's mentioned in Folklore of Discworld... Apparently in the old days there wasn't really much clear distinction between vampires/zombies/werewolves and staking them into the coffin is definitely there.