Major League Baseball

Major League Baseball is the organization that governs professional baseball’s American and National Leagues in the United States and Canada. It oversees league operations, schedules, rules, and the postseason.

American League: One of Major League Baseball’s two leagues, founded in 1901 and now comprising 15 clubs. It is one of the two leagues MLB governs.
National League founding: The 1876 establishment of the National League, the oldest continuously operating major professional baseball league. The National League’s founding marks MLB’s earliest institutional roots.
Reserve clause: A baseball contract provision that bound a player to a club beyond a single season and restricted movement between teams. Its long use gave MLB clubs extensive control over players’ careers.
Minor League Baseball: The system of professional baseball leagues below Major League Baseball, including affiliated player-development clubs. Minor leagues develop players but are not part of MLB’s two major leagues.
National League: One of Major League Baseball’s two leagues, founded in 1876 and now comprising 15 clubs. It is the older of the two leagues MLB governs.
American League founding: The American League’s 1901 emergence as a major league in competition with the National League. Its arrival created the two-league structure that defines MLB.
Major League Baseball Players Association: The labor union representing Major League Baseball players in collective bargaining and workplace disputes. Its negotiations with MLB determine player pay, rights, and labor conditions.
Negro leagues: Professional baseball leagues organized primarily for Black players during the era of major-league segregation. They operated outside MLB’s segregated structure while sustaining elite professional baseball.
Commissioner of Baseball: The chief executive of Major League Baseball, responsible for administering the sport under league rules. The commissioner exercises authority on behalf of MLB’s clubs.
National Agreement of 1903: The agreement that formalized cooperation between the National and American Leagues and established the modern World Series. It reconciled the rival leagues under an early framework for MLB.

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