Simply put, the bounce of a club is the angle from the sole of the club to the leading edge. Most often found on your wedges, the bounce is designed in the opposite direction of the loft of the club, and it is used to allow your club to move along the ground without the leading edge digging into the turf.
The amount of bounce on each club is designed for different turf conditions. If you tend to play on soft or spongy grasses, a high angle of bounce is preferred whereas golfers who are playing in relatively firm and dry conditions will benefit from lower bounce angles.
While different conditions favor different angles of bounce, so too do different players’ preferences, so it’s advisable to try out different angles of bounce before settling on your individual bag setup.