What Does Top or Bottom Mean in Baseball?

The rulebook does not use the words "top" and "bottom" as definitions. It describes what they refer to. Rule 5.01(a) says that at the time set for beginning the game the home team takes its defensive positions, the first batter of the visiting team takes his position in the batter's box, the umpire-in-chief calls "Play", and the game starts. The visiting team therefore bats first.

The definitions say an inning is the portion of a game within which the teams alternate on offense and defense and in which there are three putouts for each team, and that each team's time at bat is a half-inning. The first half-inning belongs to the visitors and the second to the home team, which matches the convention of calling them the top and the bottom, the order in which they appear on a scoreboard line score, with the visitors on the upper line.

Because the home team bats last, the game can end before the bottom half is finished. Rule 7.01(e) says a completed regulation game ends when the visiting team completes its half of the ninth inning if the home team is ahead, and that if the home team scores the winning run in its half of the ninth inning, or of an extra inning after a tie, the game ends immediately when the winning run scores.

If the home team is ahead after the top of the ninth, the bottom is not played. This is one reason the final score sometimes shows an "X" in the bottom of the ninth in a line score, which is a scoreboard convention and is not described in the rulebook.

When the score is tied after nine completed innings, play continues. Under Rule 7.01(b), each half-inning after the ninth begins with a runner on second base, who is the player in the batting order immediately preceding that half-inning's leadoff hitter. The top and bottom of each extra inning then follow the same pattern as before.

One exception shows how the order of the halves matters. If the last batter in a game hits a home run out of the playing field, the batter-runner and all runners on base are allowed to score under the base-running rules, and the game ends when the batter-runner touches home plate. In every other case the game ends the moment the winning run scores in the home half of the ninth inning, or of an extra inning after a tie.

The wording comes from the Definitions, Rule 5.01 and Rule 7.01 of the Official Baseball Rules, 2026 edition. The terms top and bottom are common usage; the rulebook describes the half-innings they name. This page does not describe scoreboard notation beyond what is said.

The rules are reviewed each year. This page was checked against the 2026 edition. More baseball pages are collected on the MLB hub, and the page about halftime in baseball covers how the game is divided.