Open to anyone and with no or few rules.
Deathmatch, sometimes specifically one in which every player is pitted against all the others.
Chaos; a chaotic situation lacking rules or control.
A major league club and all its farm teams.
The quality of being organized.
A group of people or other legal entities with an explicit purpose and written rules.
A group of people consciously cooperating.
The way in which something is organized, such as a book or an article.