Tenant
Your organization's dedicated instance of a cloud service, containing your users, data, and configuration.
In Microsoft 365, the tenant is the boundary of your directory. Users, licenses, policies, and data live inside it, and it is identified by a domain and a unique ID.
Tenant boundaries matter during mergers, acquisitions, and divestitures, where data has to move between them. Those migrations are involved projects rather than a setting to change.
Where this comes up
Tenant sits inside our identity and access work. If you are trying to work out what this means for your own environment rather than in the abstract, that is the page worth reading next, and a short call will get you a straight answer faster than either.
Related terms
Microsoft Entra ID Microsoft's cloud identity service, the account directory behind Microsoft 365 and thousands of connected applications. Guest account An external person given access to your tenant using their own organization's identity. Microsoft 365 Microsoft's subscription bundle of Office applications, email, file storage, collaboration, identity, and security services.