• Azure pay-as-you-go, also called Microsoft Online Services Program (MSOP), is a direct from Microsoft purchase of Azure for organizations of all sizes
• Microsoft Customer Agreement
• Enterprise Agreement (EA) is a direct from purchase of Azure for large organizations that can make longer term commitments.
• Cloud Solution Provider (CSP) is a method of purchasing Azure through a third-party partner.

• AAD and ARM are the two overarching entities that make up Azure.

A tenant is the organization that owns and manages a specific instance of Microsoft cloud services. It's most often used to refer to the set of Azure and Microsoft 365 services for an organization

There is a one-to-one association between a tenant and an instance of Azure AD. Consequently, the term tenant can be used as a synonym for an instance of Azure AD. This makes sense since AAD is a core part of Azure and related services.

• The top-level unit of organization in AzureRM is the root Management Group.
• Under the root Management Group there can be multiple levels of other Management Groups—up to six levels deep.
• Under Management Groups there are subscriptions.
• And under subscriptions there are Resource Groups.
• Within Resource Groups there are resources, like virtual machines