This book presents the creation of a bilingual thesaurus (Italian and English), and its conversion into an ontology system, oriented to the Cybersecurity field of knowledge term management and the identification of a replicable method over other specialized areas of study, through computational linguistics procedures, to a statistical and qualitative measurement of the terminological coverage threshold a controlled vocabulary is able to guarantee with respect to the semantic richness proper to the domain under investigation. The volume empowers readers to compile and study significant corpora documentations to support the text mining tasks and to establish a representativeness evaluation of the information retrieved. Through a description of several techniques belonging to the field of linguistics and knowledge engineering, this monograph provides a methodological account on how to enhance and update semantic monitoring tools reflecting a specialized lexicon as that of Cybersecurity to grant a reference semantic structure for domain-sector text classification tasks.