A web cache is a technology that temporarily stores copies of web pages and resources to improve loading times and reduce bandwidth usage. When a user visits a website, the cache saves the content so that if the same user or others request the same page again, it can be delivered more quickly from the cache instead of fetching it from the original server. Web caches can be found in various forms, including browser caches, proxy caches, and content delivery networks (CDNs). By using a web cache, websites can enhance performance, decrease server load, and provide a better user experience, especially during high traffic periods.