Network Address Translation (NAT) is a method to translate IP addresses between networks. It also allows a single, public IP address to be used by multiple private IP addresses. This aspect of NAT is essential for creating private networks in home and mobile routers. It's also becoming a common tool for internet service providers to manage dwindling numbers of IPv4 network addresses until the new IP addressing system, IPv6, is fully implemented.
NAT can also refer to network restrictions in multiplayer video games that prohibit certain types of multiplayer gaming connections.