A Routing method where several Servers in geographically different locations can share a single IP Address.
This is made possible since the Internets standard routing algorithm Border Gateway Protocol (BGP) will (with high probability) direct the packets to the nearest location.
This is widely used by Domain Name System (DNS) Servers.
However on long TCP connections it is possible that the best path determined by Border Gateway Protocol (BGP) changes, which can result in packets transferred in the same connection arrive at different servers. Therefore Content-Provider Networks (CDNs) generally do not use anycast even though it is possible.