What term describes a user's ability to easily navigate a website?

The correct term that describes a user’s ability to easily navigate a website is "User Experience." This concept encompasses all aspects of the end-user's interaction with a company, its services, and its products. User experience specifically includes usability—how intuitive and user-friendly a website is—and can significantly impact the satisfaction and effectiveness of user interactions.

While other terms like user engagement, user flow, and interactivity are related to how users interact with content on a website, none specifically encapsulate the entire experience of navigation like user experience does. User engagement typically pertains to the extent to which users interact with the content, user flow refers to the path users take through a website or application, and interactivity emphasizes how users can actively contribute or engage with the system rather than focusing solely on navigation ease. Thus, user experience is the most comprehensive and accurate descriptor in this context.