When my customers get started with Azure, one of the first things that trips them up is the terminology.  This is a quick primer of the terms you’ll encounter as you begin your journey.

Azure Enrollment

The Azure enrollment is an Azure usage agreement often tied to an Microsoft Enterprise Agreement.  One enrollment = one bill.  Under the enrollment you create Azure accounts, subscriptions, and ultimately resources (VMs, storage, DBs).

https://docs.azure.cn/en-us/articles/azure-global-purchasing-guidance/go-global-playbook-purchase-process-of-enterprise-azure

Azure Tenant

A tenant is a instance of Azure Activity Directory (AAD).  A tenant is similar to a Windows AD domain.  Within the AAD you can have users, groups, etc.  Each instance of Azure, O365, Dynamics, etc. requires a tenant.  These tenants can be shared or you can use a unique instance for each one.

*each subscription can use a separate tenant*

https://docs.microsoft.com/en-us/azure/active-directory/develop/quickstart-create-new-tenant

Azure Subscription

An Azure subscription is the unit where all resources (VMs, DBs, etc.) reside.  The this is the highest level in an enrollment that can incur charges.  A subscription is equivalent to an AWS account.

see also https://docs.microsoft.com/en-us/office365/enterprise/subscriptions-licenses-accounts-and-tenants-for-microsoft-cloud-offerings