User engagement refers to the level of interaction, involvement, and interest that users have with a website, app, or online content. It measures how users interact with the provided information, features, and functionalities, such as commenting, sharing, liking, or spending time on a website. High user engagement indicates that users find the content valuable, enjoyable, and relevant, leading to increased time spent on the platform, improved conversion rates, and a stronger connection between the user and the brand.