A knife (plural knives; from Old Norse knifr 'knife, dirk') is a tool or weapon having a cutting edge or blade that is usually connected to a handle or hilt. Knives, one of humanity's first tools, arose at least 2.5 million years ago, as demonstrated by the Oldowan tools. Early knives were made from sharp stones or bones that could be easily found in the environment. Modern knives are made from steel, which is much more durable than stone or bone. The term "knife crime" has been used to describe violent crimes using knives as weapons. The word "knife" comes from the old English noun cnife, cognate with the Germanic word for sword, seax. The verb form of the word is given as knife. Early knives were probably not intended for cutting food but rather for cutting meat from the bone. Evidence of this can be seen from many ancient human remains where cuts on the bones appear to have been made with something sharp. It has been suggested that these cuts may have been made by hunters to facilitate skinning their kills or to provide a convenient way to divide up the meat later. As time went on, knives became more specialized. By the Middle Ages, knives had been divided into eight types: hunting knives, bread knives, butcher's knives, paring knives, fishing knives, scalping knives and ceremonial knives.