Clasp means many things. But it can also be meant to mean a brooch, pin, clip, hook or catch. But it can never mean a Zipper. The general meaning of clasp is "a device, usually of metal, for fastening together two or more things or parts of the same thing e.g. a clasp for paper money; a clasp on a necklace " So you can use Clasp for anything that performs the same function. However, it most probably won't be clear to the person who uses the specific word like Brooch or buckle.

i've personally never heard of a clasp being used like that...a clasp can be a buckle but not necessarily a zipper or a brooch, by the way, no such thing as "broocher" a clasp is something like pulls one thing and clamps down on the other side to hold them together