round-robin tournament
tournament in which each contestant meets every other participant once (single round robin) or twice (double round robin)
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Example of a round-robin tournament with 10 participants
A round-robin tournament or all-play-all tournament is a competition format in which each contestant meets every other participant, usually in turn. A round-robin contrasts with an elimination tournament, where participants are eliminated after a certain number of wins or losses, as well as with a Swiss-system tournament, where participants are matched according to their running score.