The life-cycle of a workflow may be basically summarized to the two following steps: build-time (the process is defined) and run-time (the process definition is used to control and facilitate its enactments). Specific formalisms have been developed for defining processes and controlling their executions. The problem is that these formalisms are separate. The relation between a process definition and its executions is not made explicit. However the behaviour of a process at run-time may impact its definition. There is thus a need for weaving definition and execution aspects. Meta-modeling techniques may bring some relevant answers to this particular issue as they allow the definition of separate aspects of a system and their combination. This is what we attempt to show in this paper by studying the binding between two well-known workflow formalisms (the WfMC process definition meta-model and the OMG Workflow Management Facility).