Within the framework of developing fundamental scientific discipline “e-librarianship”, the RNPLS&T designs its electronic terminological dictionaries. The authors describe the System of Electronic Dictionaries being developed by the Russian National Public Library for Science and Technology. For today, the System comprises subject terminological dictionaries and dictionaries of abbreviations, i. e. “Electronic terminological dictionary on SIBID”, “Union terminological dictionary in e-librarianship”, “Information technologies in education: The electronic terminological dictionary”, and “Electronic dictionary of standardized abbreviations in the Russian and 25 foreign European languages for bibliographic records”. The goal is to organize and systematize the terminology in the library and information sciences and related disciplines, which is especially important in the period of intensive development of e-librarianship as a fundamental scientific discipline. The practical significance of these electronic dictionaries is evidenced by the statistics of page traffic at RNPLS&T website where the dictionaries are accessible for free loading and further use. The characteristics and design principles of the subject terminological dictionaries are analyzed; the software designed at RNPLS&T for building them is described. The focus is made on methodological guidelines on how to manage the databases of subject terminological dictionaries.