Virtual Private Cloud (VPC)

Think, your own network inside AWS.

Internet gateway

The thing that lets internet traffic into your network.

Virtual private gateway

Like internet gateway, but only from specific networks. Think work VPN or work intranet.

Direct connect

Direct connection between 1 network to AWS. This seems more like a data center to AWS connection rather than the private gateway. This seems really $$$.

Subnets

Different areas inside the VPC, public or private areas. Public has access to the internet gateway.

Network access control list (NACL)

Every packet is checked, both in and out of a subnet. Is stateless (doesn't remembers).

Security group

Think NACL, but for instances. Only checks entry, not exit (by default). Is stateful (remembers).

Route 53

AWS's own DNS system and domain registrar.

CloudFront

AWS CDN.