Blades, Knives, Etc.

Depending on the type of knife and its intended use, there are several precise alternatives:

General/Cutting: Blade, cutter
Pocket/Utility: Pocketknife, jackknife, penknife, box cutter
Kitchen/Cooking: Cleaver, chopper, butcher's knife, or blade
Combat/Hunting: Dagger, stiletto, shank, bowie knife, or switchblade
Medical/Surgical: Scalpel or lancet