Office 365 is a suite of services offered by Microsoft. It is the same Office you already know and use every day, but with a slightly different interface and many more features.
Microsoft’s branding of its Office 365 offering may have led to some confusion on how it differs from the Microsoft Office productivity suite that we’re all familiar with. So, what’s the difference?
Microsoft Office is the name still used for all of the Microsoft software applications that we use, such as Word, Excel and PowerPoint. Unlike Office 365, however, these applications can be installed on only one computer system and do not come with any cloud-based services.
Office 365, on the other hand, includes Microsoft Office applications and other productivity services, such as the SharePoint intranet site, instant web messaging using Lync, OneDrive cloud services, the Outlook Web App webmail service, and the Exchange Server e-mail server program. Office 365 plans also allow applications to be installed on multiple computers and devices. The service package is powered by the cloud, so you can access your applications and files from virtually anywhere (desktops, tablets, mobile phones, the Web), and they're always up to date.
Learn more about Office 365 here: http://office.microsoft.com/en-ca/business/what-is-office-365-for-business-FX102997580.aspx