A knife (: knives; from Old Norse knifr 'knife, dirk') is a tool or weapon with a cutting edge or blade, usually attached to a handle or hilt. One of the earliest tools used by humanity, knives appeared at least 2.5 million years ago, as evidenced by the Oldowan tools. Originally made of wood, bone, and stone (such as flint and obsidian), over the centuries, in step with improvements in both metallurgy and manufacturing, knife blades have been made from copper, bronze, iron, steel, ceramic, and titanium. Most modern knives have either fixed or folding blades; blade patterns and styles vary by maker and country of origin.
Knives can serve various purposes. Hunters use a hunting knife, soldiers use the combat knife, scouts, campers, and hikers carry a pocketknife; there are kitchen knives for preparing foods (the chef's knife, the paring knife, bread knife, cleaver), table knife (butter knives and steak knives), weapons (daggers or switchblades), knives for throwing or juggling, and knives for religious ceremony or display (the kirpan).
Knife making
Kitchen knife#Nomenclature
A modern knife consists of:
the blade
the handle
the point – the end of the knife used for piercing
the edge – the cutting surface of the knife extending from the point to the heel
the grind – the cross section shape of the blade
the spine – the thickest section of the blade; on a single-edged knife, the side opposite the edge; on a two-edged knife, more toward the middle
the fuller – a groove added to make the blade lighter
the ricasso – the flat section of the blade located at the junction of the blade and the knife's bolster or guard
the guard – the barrier between the blade and the handle which prevents the hand from slipping forward onto the blade and protects the hand from the external forces that are usually applied to the blade during use
the hilt or butt – the end of the handle used for blunt force
the lanyard – a strap used to secure the knife to the wrist
The blade edge can be plain or serrated, or a combination of both.