In the article an invariant dictionary entry of the modern universal dictionary of the Russian language is modelled. Under the microstructure of the invariant dictionary the dictionary entry, where as far as possible the full set of all the kinds of information about the title unit is presented is understood. This is phonetic, grammatical, semantic, combining, word-forming, etymological, illustrative, encyclopedic and other information. Various types of lexicographical marks and references are given. All the types of the lexicographic information are provided with illustrative examples. Notions of canonical forms, a brief and complete grammatical characteristic of the title unit, its semantization (interpretation, definition, translating equivalent), word-forming family of words etc. are explained. Microstructure of the dictionary is seen as a separate systemic part of a more sophisticated and large-scale system – the macrostructure of the dictionary, which the general principles of the structure of the lexicographic products form.