The batting order, or batting lineup, in baseball is an when nine members of the offense take their turns in batting against the pitcher in an order. The batting order is decided by the manager before the game begins, although sometimes during games, a player substitutes with another player which means they take the original player's spot. If a team bats out of order, it is a violation of baseball's rules and subject to penalty. When the whole batting order makes plate appearances (bats against the pitcher) in a single inning, it is called "batting around."
In modern American baseball, some batting positions have nicknames: "leadoff" for first, "cleanup" for fourth, and "last" for ninth. Others are known only by the ordinal numbers.