Office 365 is essentially defined as a cloud computing platform.

The one part of Office 365 that is NOT cloud computing is the desktop or mobile versions of Office, whether full versions of Office for Macs or PC’s, mobile apps for tablets or phones, or the browser-based version, Office Online, for viewing Office documents within any of the latest browser applications.

Office Online is designed to work with the most current versions of Internet Explorer, Mozilla Firefox, Chrome or Safari by going out to the Microsoft Cloud to retrieve documents in real time, although you can switch on-the-fly to the Desktop Office software to work on the same document.