If you raid a fridge, do you call the fridge a raid? No you don't.(There’s no guarantee all future instances will fit the definition of “dungeon,” and it’d just be ridiculous and flat out wrong to call something that isn’t a dungeon a dungeon, right? But even a small party of people can raid a given location, dungeon or otherwise. Just sayin’.)
If you raid Fort Knox, do you call Fort Knox a raid? No you don't.
If you raid Iraq, do you call Iraq a raid? No you don't.
Just sayin’