Noun

1. A beaten mixture of flour and liquid (usually egg and milk), used for baking (e.g. pancakes, cake, or yorkshire pudding) or to coat food (e.g. fish) prior to frying

   To the dismay of his mother, the boy put his finger into the cake batter.

2. The person who tries to hit the ball in a sport like baseball

   The first batter hit the ball into the corner for a double.

3. A batsman. Used under the modern fashion for expunging gender from all words, but in fact women cricketers refer to themselves as batsmen (ie. it's already gender-neutral, see the batsman article).
4. A binge, a heavy drinking session.

   When he went on a batter, he became very violent.

5. A slope.

   Hydroseeding of unvegetated batters is planned.