(Web Services Business Process Execution Language) An XML-based language developed by IBM, BEA Systems, Microsoft and others for defining business processes in a Web services environment. As of Version 2.0, WSBPEL became an OASIS standard. The acronym was previously BPEL4WS, and BPEL without the WS is commonly used. WSBPEL differs from BPML and other business process languages by providing both an abstract level and a low level. At the abstract level, it is used to define broader parameters and constraints while keeping details hidden. At the low level, it defines executable processes. WSBPEL evolved from Microsoft's XLANG and IBM's WSFL. See UDDI, Web services, XLANG and WSFL.