A content delivery network, also known as a content distribution network or CDN, is a geographically-distributed network of servers that deliver static content to users.
Each edge server in the CDN caches static assets (like web pages, images, video, and audio) from the origin, or host server.
A CDN has several points of presense (PoPs), which is a location that has a group of edges servers. Each PoP sends content to the users that are physically closest to it.
CDNs help deliver static and dynamic online content faster and more reliably, and provides a layer of redundancy for websites.