A sword is a blade weapon used primarily for cutting or thrusting. The precise definition of the term varies with the historical epoch or the geographical region under consideration. A sword in the most narrow sense consists of a straight blade with two edges and a hilt. However, in nearly every case, the term may also be used to refer to weapons with a single edge (backsword).
The word sword comes from the Old English sweord, cognate to swert, Old Norse sverð, from a Proto-Indo-European root *swer- “to wound, to cut”. Non-European weapons called “sword” include single-edged weapons such as the Middle Eastern saif, the Chinese dao and the related Japanese katana. The Chinese jian is an example of a non-European double-edged sword, like the European models derived from the double-edged Iron Age sword.