I wonder whether there exists any difference between an edge/blade guard/protector and a sheath.
I'm trying to name the following item:
Since the object in the picture clearly encloses the whole of the blade and so it qualified as a sheath. The question then is whether any of the the other options is appropriate. I would have said that an edge guard or protector was something which just fitted over the edge to protect it or the user from harm but which does not cover the whole blade. A blade guard could have wider application than edge guard and would seem correct for the particular object shown. You do see edge guards on other sharp objects as well like chisels, saws and scraper blades.