A Web-based version of Microsoft's Office suite of enterprise-grade applications. Office 365 is delivered to users through the cloud and includes Exchange Online for email, SharePoint Online for collaboration, Lync Online for unified communications, and a suite of Office Web Apps, Web-based versions of the traditional Microsoft Office suite of applications.
Know more about it here :
http://products.office.com/en-us/business/explore-office-365-for-business
