French mêlée, from Old French meslee, from mesler to mix
The French term is the feminine past participle of the verb mêler "to mix". Nominalized, it refers to any confused tangle or agitated scramble, in particular unordered combat. The term descends from Old French meslede, from Vulgar Latin misculāta "mixed", from Latin miscēre "to mix"; compare mélange, milieu. Like other common foreign-derived terms used in English, the word is sometimes written without accents (i.e. as "melee").
Melee French: mêlée, the French spelling is also quite frequent in English writing), generally refers to disorganized close combat involving a group of fighters. A melee ensues when groups become locked together in combat with no regard to group tactics or fighting as an organized unit; each participant fights as an individual.
During the Middle Ages, tournaments often contained a mêlée consisting of knights fighting one another on foot or while mounted, either divided into two sides or fighting as a free-for-all. The object was to capture opposing knights so that they could be ransomed, and this could be a very profitable business for such skilled knights as William Marshal. There was a tournament ground covering several square miles in northern France to which knights came from all over Europe to prove themselves in quite real combat. This was, in fact, the original form of tournaments and the most popular between the twelfth and thirteenth centuries—jousting being a later development, and one that did not completely displace the mêlée until many more centuries had passed. The original mêlée was engaged with normal weapons and fought with as much danger as a normal battle. Rules slowly tempered the danger, but at all times the mêlée was more dangerous than the joust.
The term "melee" has been extended to refer to other forms of combat, such as a naval or armor battle that is fought at abnormally close range with little central control once it starts. The Battle of Trafalgar became a melee when the British ships broke the French and Spanish line, precipitating a ship-to-ship battle. In this instance, the melee was planned; Admiral Nelson used the superior fighting qualities of his crews to offset the greater French and Spanish numbers.
It is also used in sport. For example, the Australian Football League has an official melee rule which is used to fine players involved in large on-field brawls, regardless of whether or not they throw punches.