Abstract: In the current global environment, a clear understanding and definition of the terms "security" and "national security" are becoming critically important for the development of effective public policy and legal mechanisms. Inconsistencies and uncertainties in legal terminology lead to legal conflicts and difficulties in interagency cooperation. In addition, ambiguity and blurring of terms can negatively affect public understanding and trust in public authorities and their actions in the field of security. The article examines the key aspects of the legal definitions used in the legislation of the Russian Federation related to the concepts of "security" and "national security". The article analyzes the evolution of these concepts in legal and political contexts, as well as their interrelationship and influence on the formation of a state strategy in this area. Particular attention is paid to the differences in the interpretation of these terms in national law, as well as law enforcement practice. The methodological basis of the research is the universal dialectical method of cognition. Along with it, general scientific and private scientific methods were used: comparative legal, concrete sociological research, formal logical, systemic, structural and functional, formal legal, axiomatic. As a result of the conducted research, it is concluded that accurate and unambiguously understood terminology is important for effective security in modern conditions when the world is facing new challenges and threats. In this scientific work, new definitions of the concepts of "security" and "national security" are formulated, which fully reflect the distinctive features of each of them. The proposed formulations emphasize the importance of not only studying, but also critically analyzing these categories in the context of the dynamic changes taking place in the modern world. The definitions formulated by the author will certainly make it possible to take a significant step towards strengthening the legal understanding of the existing security system in the modern Russian state, which will allow the federal legislator, including better protection of the interests of citizens and the country as a whole, using competent definitions.