Major League Baseball is the top-tier level of professional North American Baseball. Major League Baseball refers to the organization which operates the two professional baseball leagues of North America, the National League and the American League. Teams play a 162 game season and American League play differs from National League play in that American League teams have a designated hitter who bats for the pitcher. Neither the American League nor the National League are considered legal entities in their own rights, so Major League Baseball effectively acts as an umbrella organization for a single league.
Major League Baseball operates under the direction of a commissioner, and in this capacity it hires umpiring crews, negotiates media contracts, marketing, and labor. Major League Baseball has a broad administrative reach, and maintains a controlling relationship over most aspects of minor league baseball as well. Major League Baseball consolidates marketing efforts for both leagues and exerts control over all 30 individual team websites.