FIDDLE: Federated Infrastructure Discovery and Description Language Considerable efforts have been spent on designing architectures to manage heterogeneous resources across multiple administrative domains. Specific fields of application are federated cloud computing (Intercloud) approaches and distributed testbeds, among others. An important interoperability challenge that arises in this context is the exchange of information about the provided resources and their dependencies. Existing work usually rests upon schematic data models, which impede the discovery and management of heterogeneous resources between autonomous sites. One way of addressing this issue is to exchange semantic information models. In this paper, we exploit such approaches to formally define federations, including their infrastructures and the life-cycle of the offered resources andservices. The requirements of this work have been derived from several research projects and the results are in process of being standardized by an international body. The main contribution of this work is a higher level (upper) ontology and initial integration concepts for it. These contributions form a basis for further work in the general context of distributed semantic resource management.