What a cloud region is
A cloud region is a defined geographic area where a provider operates infrastructure and offers services. Organizations often select a region based on latency, service availability, cost and where users or data are located.
A region can contain multiple independent facilities or availability zones depending on the provider's architecture.
What an availability zone is
An availability zone is intended to provide a failure-isolated location within a region. Zones are connected, but designed so that one facility-level problem is less likely to affect every zone at once.
Applications can distribute components across zones to reduce dependence on a single physical location.
Resilience requires application design
Cloud infrastructure provides building blocks, but applications must actually use them correctly. A database deployed in one zone remains a single-zone dependency even if the provider operates many zones.
Teams should identify critical dependencies, define recovery objectives and test how services behave when components become unavailable.