Network Address Translation - Definition from the Hotspot Shield Glossary
NAT involves the translation of IP addresses within a computer network to enable a route to use one single address instead of having to deal with many.
Within a computer network, each device connected to the network will have its own designated IP address - Instead of using these IP addresses when sending and receiving traffic from the internet, a route will use NAT to translate those multiple IP addresses into one single address. When other devices attempt to connect or communicate with a network, they will only see that single IP address and not the addresses of each individual device on the network - This provides a great level of security. If a devices is allowed access to the network and wants to connect to a single device, a NAT table is used to re-translate the group IP address into the devices individual IP address.