What does a batting average mean?

Answer 1

It means you have hit 1 out of every 2 balls thrown at you.

Answer 2

It means that you get on base via a base hit (NOT walk, or hit by pitch) a relatively high percentage of the time, often via singles. This is usually at the expense of "hitting for power," which refers to the tendency to hit lots of doubles or home runs.

Answer 3

the number of hits you have over the number of at bats you have