AWS component that allows resources in a VPC to connect to the internet. Like the main door of a building that connects the inside to the outside world.
Web servers in a public subnet use an Internet Gateway to serve websites to users on the internet.
AWS Internet Gateway (IGW) is a VPC-attached gateway that enables internet connectivity for resources with public IPs and appropriate routes. Other clouds don’t have a single identically named, attachable “gateway” object; similar outcomes are achieved using each provider’s VPC/VNet routing plus a managed internet edge (public IPs, NAT, and firewall/routing constructs).