Bounce rate
Bounce rate is the proportion of visits that end after a single page, with no further interaction. A high bounce rate can mean visitors did not find what they wanted — or that a single page answered their question completely, so consider it alongside the page's purpose, rather than as a judgement on its own.
Exactly what counts as 'no further interaction' varies by analytics tool and has changed over time (some tools now count a session as engaged if it lasts a minimum length of time, even with no second page view), so bounce rate is only meaningfully comparable across pages measured the same way.