Regions and Availability Zones

Regions - a set of related, interconnected datacenters which are no more than a few miles apart; you must select a region when creating most Azure services; there are currently 60+ active or planned worldwide; the most of any cloud computing provider; you will not have access to all of them because some of them are restricted

Region Pairs - Each region is “paired” with one other region, which provides the highest-speed, lowest-latency connection between them; Azure treats them as a pair, trying to minimize the chance of them both going down at the same time. Good as a place to store backups and have redundant servers running.

Sovereign Regions - The regions are dedicated to specific sovereign entities, and isolated from the rest of Azure regions. For example, Azure Government - US and Azure China.

Availability Zones - Unique physical locations within an Azure region, made up of one or more datacenters; there is a minimum of three zones in each region; you can manually place your resources in an availability zone for highest availability

Azure Datacenter - a group of interconnected buildings in the same location that contain all the servers, power, wiring, and internet connectivity to run Azure services