Network Address Translation (NAT) is a networking technique that allows multiple devices on a local network to share a single public IP address. This is important because many internet service providers (ISPs) only provide a single public IP address to their customers. NAT allows these customers to connect multiple devices to the internet without having to pay for additional public IP addresses.
NAT also provides a level of security by hiding the internal IP addresses of devices on the local network from the internet. This can help to protect these devices from attack.