The users' demand has determined the need to manage the growing new technical maritime terminology which includes very different domains such as the juridical or commercial ones. A terminological database was built by exploiting the computational tools of ItalWordNet (IWN) and its lexical-semantic model EuroWordNet. This paper concerns the development of database structure and data coding, relevance of the concepts of 'term' and 'domain', information potential of the terms, complexity of this domain and detailed ontology structuring recently undertaken and still in progress. Our domain structure is described defining a core set of terms representing the two main sub-domains specified in 'technical-nautical' and 'maritime transport' terminology. These terms are sufficiently general to be the root nodes of the core ontology we are developing. They are mostly domain-dependent, but the link with the Top Ontology of IWN remains, endorsing either general and 'foundation' information, or detailed description directly connected with the specific domain. This structure seems to be the most appropriate to characterize the main conceptual schemas that people of the technical-nautical or maritime transport "world" actually use, namely activity plans, navigation management, etc. Also a set of acronyms has been codified to represent their ever increasing use in maritime terminology. Through the semantic relations linking the synsets, every term 'inherits' the IWN Top Ontology definitions and becomes itself an integral part of the structure. While codifying a term in the maritime database, the reference is at the same time allowed to the Base Concepts of the terminological ontology embedding the term in the semantic network, showing that upper and core ontologies make it possible for the framework to integrate different views on the same domain in a meaningful way.