In baseball

Baseball

Baseball is a bat-and-ball sport played between two teams of nine players each. The aim is to score runs by hitting a thrown ball with a bat and touching a series of four bases arranged at the corners of a ninety-foot diamond...

, hit by pitch (HBP), or hit batsman (HB), is a batter or his equipment (other than his bat) being hit in some part of his body by a pitch from the pitcher

Pitcher

In baseball, the pitcher is the player who throwsthe baseball from the pitcher's mound toward the catcher to begin each play, with the goal of retiring a batter, who attempts to either make contact with the pitched ball or draw a walk. In the numbering system used to record defensive plays, the...

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Per baseball official rule 6.08(b), a batter becomes a baserunner

Baserunning

In baseball, baserunning is the act of running around the bases performed by members of the team at bat.In general, baserunning is a tactical part of the game with the goal of eventually reaching home to score a run. In fact, the goal of batting is generally to produce baserunners, or help move...

 and is awarded first base when he or his equipment (except for his bat):

• is touched by a pitched ball outside of the strike zone
  Strike zone
  In baseball, the strike zone is a conceptual right pentagonal prism over home plate which defines the boundaries through which a pitch must pass in order to count as a strike when the batter does not swing.-Definition:...
  
  ,
• and he attempts to avoid it (or had no opportunity to avoid it),
• and he did not swing at the pitch.

If all these conditions are met, the ball is dead, and other baserunners advance if they are forced to vacate their base by the batter taking first.