A ball that travels outside the boundary line is a __ Fair ball foul ball homerun out

## Step 1<br />In baseball, when a ball is hit outside the boundary line, it is referred to as a "foul ball". This term is used when the ball is hit outside the field of play, which is the area between the foul lines.<br />## Step 2<br />The other options provided, "Fair ball", "homerun", and "out", do not accurately describe a ball that travels outside the boundary line. <br />## Step 3<br />A "Fair ball" is a ball that lands in the field of play, a "homerun" is a specific type of fair ball that is hit out of the field of play, and an "out" is a term used when a player is not allowed to continue playing due to a rule violation.