Legal concepts and the concepts used "in law" (specifics of terms used in "legal norms"). "Legal" and "non - legal" concepts. Abstract and so-called "unclear" concepts, their functions in legal rules and normative systems. Interpretation as a "function" (relation) matching concepts and terms with "significance" and "meaning". Logic and semantic aspects of interpretation. Ïnterpretation within normative systems. Interpretation – setting signifikance or meaning of cencepts via „langue of law“, „interpretation“ – clarification, explanation of a „legal concept“ through „general“, and „common“ language. Interpretative plurality (Interpretation theory of Razov), from the point of view of consistency of normative systems, possibilities and point of its restriction. Unambiguity, or possibly, a significant restriction of the interpretation plurality of legal concepts as a prerequisite for narrowing the interpretation spectrum of legal rules and support of normative systems consistency.