1.catcher

a. the player responsible for the area between 2nd and 3rd base
b. the player on the mound in the middle of the field
c. the player positioned behind home plate
d. occurs when a fielder fails to make a play
e. a ball hit outside the 1st or 3rd base lines
f. a pitch thrown outside the strike zone
g. area over home plate between the armpits and the knees
h. a pitcher can throw three of these to get a batter out
i. the official behind home plate
j. when a pitcher throws out a base runner

c. the player positioned behind home plate. The catcher is responsible for catching pitches thrown by the pitcher, blocking wild pitches, and making plays at home plate to prevent the opposing team from scoring runs.

The term "catcher" refers to the player positioned behind home plate. This player is responsible for catching the pitches thrown by the pitcher and plays a vital role in the defense of the team.

To determine the correct answer, we need to go through the options and identify the one that matches the description.

a. The player responsible for the area between 2nd and 3rd base: This is the shortstop or third baseman. It is not the role of a catcher.

b. The player on the mound in the middle of the field: This refers to the pitcher. Again, not the role of a catcher.

c. The player positioned behind home plate: Yes, this is the correct description of a catcher.

d. Occurs when a fielder fails to make a play: This is an error. It is not directly related to the catcher.

e. A ball hit outside the 1st or 3rd base lines: This is a foul ball. It does not specifically relate to the catcher.

f. A pitch thrown outside the strike zone: This is a ball, but it doesn't describe the catcher's role.

g. Area over home plate between the armpits and the knees: This is the strike zone. While catchers are involved in determining balls and strikes, it's not the definition of a catcher itself.

h. A pitcher can throw three of these to get a batter out: This refers to strikes. While the catcher plays a role in receiving and calling the pitches, it doesn't define what a catcher is.

i. The official behind home plate: This is the home plate umpire. Not the role of a catcher.

j. When a pitcher throws out a base runner: This is a pickoff or caught stealing, and it's not specifically the role of the catcher.

Therefore, the correct answer is c. the player positioned behind home plate.

1. Catcher: c. the player positioned behind home plate

The catcher is the player positioned behind home plate.