Hmmm... interesting question. In the beginning the term was coined in Europe where they do have flint (seems to have some translucency). Knapping is the art of making stone tools. For some discussions I also point out that arrow heads, arrow points and projectile points are all tools as opposed to weapons as their original intent was for hunting and/or ceremonial more so than killing other people. I have not been able to find any information which provides a very solid distinction between Chert and Flint. I have heard that like granite and obsidian, they are geologically/technically the same thing. Hmmm .... another can of worms. Kind of like folks referring to deer horns when they are actually antlers. Semantics to say the least is some cases, but certainly not all!
So: Knapping = the creation of stone tools regardless of the material
Arrow/projectile + point, head = a pointy, sharp tool designed to penetrate something whether it is a stump, straw bale, foam target, food, or the enemy without.
Just my cent of two after taxes.
Ben