A sword is a long edged weapon that can be used to reduce or thrust. The exact definition of the term varies with the historical period or geographical area under consideration. The sword consists of long blades attached to the hilt. The blade can be straight or curved. The point of thrust sword is straight. A sharp sword has a sharp cutting edge on one or both sides of the blade and is more flexible. Many swords are designed for fencing and fencing.

Historically, sword evolved from dagger in bronze age. The earliest specimens can be traced back to 1600 BC. Later "Iron Age" sword is still quite short, there is no cross guard. Spatha, developed in the late Roman army, became the forerunner of the European sword in the middle ages. It was originally used as a sword in the period of immigration. Only in the middle ages did it develop into a classical armed sword with cross guards. The word sword continues the Old English, sweord.

The use of the sword is called fencing, or (in the early modern or modern context) fencing. In the early modern times, the design of Western swords can be roughly divided into two forms, i.e. forward charging swords and military swords.

Powerful swords, such as rapiers and final swords, are designed to quickly pierce the target and cause deep stabs. Their long, straight, light and well-balanced design makes them highly maneuverable and deadly in duels, but they are quite ineffective in carrying out large-scale cutting or cutting movements. The bow and thrust aimed at the target can end the fight with the tip of the sword in a few seconds, leading to the development of fighting style, which is very similar to modern fencing.

Sabre and similar blades, such as machetes, are made heavier and more often used in war. The sword's long blade is bent and balanced forward, and can kill (usually on horseback) multiple enemies, so it has a deadly effect on the battlefield. Most sabres also have sharp tips and double-edged blades, so they can pierce soldiers when cavalry charge. Until the beginning of the 20th century, sabres were used on the battlefield. Entering the Second World War, the U.S. Navy kept tens of thousands of strong daggers in its armory, many of which were distributed to the Marine Corps in the Pacific Ocean as jungle machetes.

Non European weapons known as "swords" include single blade weapons such as the Middle East scimitar, the Chinese island and related samurai swords. China's Jian is an example of a non European double-edged sword, just like the European model derived from the double-edged Iron Age sword.