A Web Part is an Sharepoint 2010 server control that is added to a Web Part Zone on Web Part Pages by users at run time. Web Parts are an integrated set of controls for creating Web sites that enable end users to modify the content, appearance, and behavior of Web pages directly from a browser. The Web Parts control set is a group of components that work together to enable developers to create Web pages where users can modify the user interface (UI) directly from a browser. The UI controls all derive from the Part class, and they compose the primary UI on a Web Parts page.
