Availability Zones (AZs) are distinct locations within a Region, each designed as an independent zone with its own power, networking, and connectivity. They are made up of a single or multiple Data Centers
Deploying applications across multiple AZs is an important part of building a resilient and highly available architecture. So that if one AZ were to fail, your application would still be running in the other AZs.
Hierarchy
Regions are made up of Availability Zones, while Availability Zones are made up of data centers.