Define 'bounce rate' in website performance.

Bounce rate specifically refers to the percentage of visitors who land on a website and leave without navigating to any other pages within that site. This metric is crucial for assessing the effectiveness of a website's content and design in engaging users. A high bounce rate may indicate that visitors are not finding what they expected or that the website does not meet their needs, which could prompt further analysis and optimization.

In contrast to other choices, which discuss different aspects of website performance, such as user engagement (viewing multiple pages), retention (returning visitors), and conversion (completing a purchase), the definition of bounce rate directly focuses on the single-page view incident. Thus, it is essential for marketers and webmasters to monitor this metric to improve user experience and increase engagement on the site.