A Round Robin tournament or all-play-all tournament is a type of group tournament in which each participant plays every other participant an equal number of times. In a Single Round Robin schedule, each participant plays every other participant once. If each participant plays all others twice, this is frequently called a Double Round Robin. The term is rarely used when all participants play one another more than twice, and is never used when one participant plays others an unequal number of times.
The term Round Robin is derived from the French term ruban, meaning "ribbon". Over a long period of time, the term was corrupted and idiomized to robin.
See also: Pairing Systems