An AWS NAT Gateway is a managed service offered by Amazon Web Services (AWS) that allows you to use Network Address Translation (NAT) to enable instances in a private subnet to connect to the internet or other AWS services, while still keeping them secure.

When you create a NAT Gateway in AWS, you can configure it to handle outbound traffic from one or more private subnets in your Virtual Private Cloud (VPC). The NAT Gateway then translates the private IP addresses of instances in the private subnet into its own public IP address, allowing the instances to access the internet or other AWS services without exposing their private IP addresses.

NAT Gateway is a fully-managed service, which means that AWS handles all of the configuration, scaling, and maintenance for you. It is highly available and scales automatically to handle large amounts of traffic.

Using a NAT Gateway in AWS is a common practice for securely connecting resources in a private subnet to the internet or other AWS services, while also protecting the resources from direct access from the internet.