In baseball, an at bat (AB) or time at bat is a batter's turn batting against a pitcher. An at bat is different from a plate appearance. A batter is credited with a plate appearance regardless of what happens during their turn at bat, but a batter is charged with an at bat only if that plate appearance does not have one of the results enumerated below. While at bats are used to calculate certain statistics, including batting average and slugging percentage, a player can qualify for the season-ending rankings in these categories only if they accumulate 502 plate appearances during the season.

In baseball, batting is the act of facing the opposing pitcher and trying to produce offense for one's team. A batter or hitter is a person whose turn it is to face the pitcher. The three main goals of batters are to become a baserunner, to drive runners home or to advance runners along the bases for others to drive home, but the techniques and strategies they use to do so vary. Hitting uses a motion that is virtually unique to baseball and its fellow bat-and-ball sports, one that is rarely used in other sports. Hitting is unique because it involves rotating in the horizontal plane of movement, unlike most sports movements which occur in the vertical plane.