The 'Bounces' metric shows the number of visits that contained exactly one hit. You can use this metric to understand the ratio of bounce to non-bounce traffic you get, to see the top entry pages that cause visitors to bounce, or to see how the total number of bounces trend over time.
How this metric is calculated
If a visit consists of exactly one hit, the hit is considered a bounce.
If a visitor fires both a page view and link tracking call, the visit is not considered a bounce. Consider using Single page visits instead.