Specifically, a shavette is a shaving tool with a disposable blade, either it’s a fixed or a folding blade which looks similar to a straight razor if put it on the table, but the only difference a shavette has is, it has a small tiny slot to slide in your shaving blade in it at the front edge. Unlike a straight razor with which you have to take care of its fixed blade the shavette does not require this as the blade is disposable.
Both "invented" by Gillette: Which Do You Believe To Be The Best?
Interestingly enough Gillette invented the safety razor at the turn of the last century but once their patent expired everyone started manufacturing them using a standard shape blade and profits tumbled for Gillette, who then moved onto cartridge razors and kept tweaking their design to ensure the patents never ran out.
Both these razors are the very best in their class.