In this paper, we propose a versatile disambiguation approach which can be used to make explicit the meaning of structure based information such as XML schemas, XML document structures, web directories, and ontologies. It can be of support to the semantic-awareness of a wide range of applications, from schema matching and query rewriting to peer data management systems, from XML data clustering to ontology-based automatic annotation of web pages and query expansion. The effectiveness of the achieved results has been experimentally proved and is founded both on a flexible exploitation of the structure context, whose extraction can be tailored on the specific application needs, and of the information provided by commonly available thesauri such as WordNet. Categories and Subject Descriptors: H.3.1 [Information Storage and Retrieval]: Content Analysis and Indexing — linguistic processing General Terms: Algorithms.