The term SharePoint can refer to any of three related current Microsoft products which run on Windows Server 2003:

• Microsoft Office SharePoint Server 2007 (MOSS) - The next iteration of Microsoft Office SharePoint Portal Server. Includes the functionality previously included in both SPS and Microsoft Content Management Server 2002. Product is due to be released during the first quarter of 2007.
• Windows SharePoint Services (WSS) - a free Windows server component that provides collaboration and intranet services
• Microsoft Office SharePoint Portal Server (SPS) - a portal based collaboration and document management that extends Windows SharePoint Services

The term Sharepoint may also refer to the original release called Sharepoint Portal Server 2001, Sharepoint Team Services (STS) which ran on Windows 2000 Server

Windows Server System

Sharepoint