It is a term to identify the next batter in the line up after the current batter.
It's called a force. The runner is being forced to proceed to the next base by the batter/runner.
The next batter that is waiting to bat is referred to as being on deck.
If the pitch count is at 2 strikes and 3 balls that is a "full count" meaning the next pitch is the last for that batter. (For all you critics; this is because in softball, if the third strike is fouled out of play the batter is out)
A strike in softball is when a pitcher pitches a softball to the batter [located in the batter box in front of the catcher] and the batter misses. When it is a strike, it is thrown in a particular area from the batter's armpits to the bottom of their knees.
Grand Slam
By striking out.
The next batter is called the "on deck batter." The one after is referred to being "in the hole."
The perfect softball hit is when the batter is able to reach on base because of the hit. The perfect softball hit is also when you are able to advance the runner to the next base or have the runner get a score. Homerun
He's at the on deck circle. Usually called the on deck batter
designated batter
The batter watches a strike go by and doesn't swing the bat. A batter swings at a strike and misses. A batter swings at a ball and misses. A batter could also attempt to bunt on the third strike, bunting it foul would lead to the batter being called out.