Amazon cloud computing resources are hosted in multiple locations world-wide.
These locations are composed of AWS Regions and Availability Zones (AZ).
AWS Region is a separate geographic area.
Each AZ is a physical data center in the region
AWS Global Infrastructure (Image source: aws.amazon.com)
Availability Zones
Availability Zone is one or more discrete data centers with redundant power, networking, and connectivity in an AWS Region.
AZs in an AWS Region are interconnected with high-bandwidth, low-latency networking, over fully redundant, dedicated metro fiber providing high-throughput.
Each availability zones are isolated from disasters.
Some resources does not require regions and are termed as global.