Microsoft 365
Also known as M365, Office 365
Microsoft's subscription bundle of Office applications, email, file storage, collaboration, identity, and security services.
It is the platform most businesses now run on, and the distinction from the old Office 365 name is less tidy than it sounds. Business Premium and the Microsoft 365 enterprise plans add Windows licensing and Intune device management alongside the applications. Business Basic, Business Standard, and the Office 365 plans cover the productivity services only, despite two of those carrying the Microsoft 365 name.
Because so much sits inside one tenant, the configuration decisions have outsized consequences. The same subscription can be well secured or wide open depending on choices that are not made for you by default.
Where this comes up
Microsoft 365 sits inside our microsoft 365 and cloud 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.