First Contentful Paint (FCP) is a performance metric that measures the time from when a page starts loading to when any part of the page's content is rendered on the screen. This could be text, images, or other elements. FCP is crucial for assessing a user's perception of a page's load speed; a faster FCP indicates that the page is loading efficiently, leading to a better user experience.

Improving FCP involves optimizing server response times, leveraging browser caching, and minimizing render-blocking resources.