The article focuses on the double denotation principle as one of the main principles to stipulate the systemic character of language along with hierarchy and categorization principles. Denotational hierarchy supported by symbolic features both of language as a whole and word-lexeme helps clearly reveal the multilateral structure of the plane of content typical for paradigmatically related language units. The main goal of the research is to state that the systemic approach applied to bilaterally meaningful language units serves to reveal a complex structure of both - the plane of expression and the plane of content. The authors demonstrate the novelty of the procedure through the analysis of word and lexeme within their notional and language content and their symbolic, semantic and structural characteristics. Double denotation is illustrated through describing lexicographic means of noun entries in the modern Russian language defining dictionaries. The results obtained in course of the study could be applied in the theoretical description of language system as a whole and its plane of content within cognitive sciences domain. They are also proper in educational process to teach philological and linguistic courses in general linguistics, linguistic semantics and semiotics.