A Work Product Descriptor represents a
WorkProductDefinition in the
context of one specific Activity. Every breakdown structure can define
different relationships of
WorkProductDefinition Descriptors to
TaskDefinition Descriptors and Role Descriptors. Therefore one
WorkProductDefinition can be represented by many Work Product
Descriptors each within the context of an
Activity with its own set
of relationships. *
It's an element of the SPEM2 specification of the OMG organization
(http://www.omg.org/).