A knife's any cutting edge or blade, handheld or otherwise, with or without a handle. Knives were used at least two-and-a-half million years ago, as evidenced by the Oldowan tools. Originally made of rock, flint, and obsidian; knives have evolved in construction as technology has with blades being made from bronze, copper, iron, steel, ceramics, and titanium. Every culture has a unique version of the knife. A knife may be either a fixed-blade or a folding version with blade patterns and styles a… (More on Knife)