Computing paradigms such as object and component have emphasized the reuse through separation of concerns and information hiding. The concept of service is an evolution of these paradigms to emphasize loose-coupling in order to develop software as composition of reusable, loosely coupled units of software. The service-oriented computing (SOC) is working to principle the service towards the realization of service-oriented software (SOS). Meanwhile, Web services use the Internet and standards such as XML to challenge the realization of SOC. Yet, we still need a comprehensive Web services architecture that captures the properties of all the layers of the Web services stack, from wrapping, describing, deploying, registering, managing, monitoring, and discovering basic software units to recursively composing software. This work proposes a metadata for such architecture that represents the Web services with respect to four perspectives: service specification, service deployment, service as wrapper of legacy systems, and service as a unit of composition of software supporting business processes. The metadata is then used as framework and guidance for SOS development life cycle, where each perspective is considered as a level of abstraction towards the development of the SOS.