Microsoft Office is a collection of office-related applications. Each application serves a unique purpose and offers a specific service to its users. For example, Microsoft Word is used to create documents. Microsoft PowerPoint is used to create presentations. Microsoft Outlook is used to manage email and calendars. There are others as well.
Because there are so many applications to choose from, and because not every user needs all of them, Microsoft groups the applications together in collections called suites. There’s a suite of applications for students, a suite for home and small business users, and a suite for large corporations. There’s even a suite for schools. Each of these suites is priced based on what’s included in it.