the more heavily padded glove the catcher and first baseman are allowed to wear, which has the four fingers combined into one unit.

a runner caught between bases and chased down by two fielders to make a tag on him.

a runner reaching base.

the star pitcher on a team.

a claim by the fielding side to an umpire that a rules violation has taken place.

if a fielder throws the ball to another fielder who makes an out, he's credited with an assist.

an appearance by a hitter.

a barrier behind home plate to stop the ball if the catcher misses it.

if the pitcher doesn't pitch when he's started his pitching motion, it's a balk and runners are awarded an extra base.

a pitch which is called outside the strike zone, and which the hitter doesn't try and swing at.