WBS Elements 
WBS Elements
WBS elements are the only structural element in work breakdown structures. They describe either a certain task or a partial task that is subdivided further.
According to DIN 69 901 those elements in a work breakdown structure that are not subdivided are referred to as "work packages".
In the Project System a work package is not a data object. A work package can be represented in the SAP System by a WBS element or an activity.