A tournament (IPA 1) is a competition involving a relatively large number of competitors, all participating in a sport or game. More specifically, the term may be used in either of two overlapping senses:

1. One or more competitions held at a single venue and concentrated into a relatively short time interval. Some game clubs focus on preparing members for such tournaments. Chess clubs, for instance, frequently employ similar ranking systems, chess clocks, and etiquette to those used in chess tournaments.
2. A competition involving multiple matches, each involving a subset of the competitors, with the overall tournament winner determined based on the combined results of these individual matches. These are common in those sports and games where each match must involve a small number of competitors: often precisely two, as in most team sports, racket sports and combat sports, many card games and board games, and many forms of competitive debating. Such tournaments allow large numbers to compete against each other in spite of the restriction on numbers in a single match.

These two senses are distinct. All golf tournaments meet the first definition, but while match play tournaments meet the second, stroke play tournaments do not, since there are no distinct matches within the tournament. In contrast, football (soccer) leagues like the Premier League are tournaments in the second sense, but not the first, having matches spread across many stadia over a period of up to a year. Many tournaments meet both definitions; for example, the Wimbledon tennis championship.

A tournament-match (or tie or fixture or heat) may involve multiple game-matches (or rubbers or legs) between the competitors. For example, in the Davis Cup tennis tournament, a tie between two nations involves five rubbers between the nations' players. The team that wins the most rubbers wins the tie. In the later rounds of UEFA Champions League of football (soccer), each fixture is played over two legs. The scores of each leg are added, and the team with the higher aggregate score wins the fixture, with away goals used as a tiebreaker and a penalty shootout if away goals cannot determine a winner.

Knockout tournaments

A knockout tournament is divided into successive rounds; each competitor plays in at most one fixture per round. The top-ranked competitors in each fixture progress to the next round. As rounds progress, the number of competitors and fixtures decreases, and the final round consists of just one fixture, the winner of which is the overall champion.

In a single-elimination tournament, only the top-ranked competitors in a fixture progress; in 2-competitor games, only the winner progresses. All other competitors are eliminated. This ensures a winner is decided with the minimum number of fixtures. However, most competitors will be eliminated after relatively few matches; a single bad or unlucky performance can nullify many preceding excellent ones. Some single-elimination tournaments such as NBA use a multiple-game format, in which teams would play each other more than one game (e.g. best-of-seven series in NBA) in order to determine who is the winner of this round. Other knockout formats provide a "second chance" for some or all losers.