1 Used to indicate the number of wickets lost by the batting side at any moment in time.
For example, at tea the batting side was 167 for 4 indicating that they had scored 167 runs but had lost 4 wickets in the process. In some parts of the cricketing world the format is 4 for 167.

2 The number of wickets credited to a bowler in an innings in relation to the number of runs conceded.
For example 6 for 56 indicates that the bowler has been credited with 6 wickets and has conceded 56 runs.