At bat

In baseball statistics, an at bat (AB) is a statistic used to calculate other data such as batting average. A player has an "at bat" every time he comes to bat except under the following circumstances:

He receives a base on balls (BB).
He is hit by pitch (HBP).
He hits a sacrifice fly or a sacrifice bunt.
He is awarded first base due to interference or obstruction.
The inning ends while he is still at bat (due to the third out being made by a runner caught stealing, for example).