Security is one of the most ambiguous, contested, and debated ideas in the conceptual framework of international relations. The “traditional” perspective has been severely contested as new approaches develop, and the concept of security has been reworked in all its fundamental components and dimensions, from object and reference to range and security instruments. Likewise, the discussion over the definition and characterization of international security systems, namely regarding competitive security, common security, cooperative security, collective security, and security community, continues to be very lively. Starting from these debates, and in the light of the current international situation, we propose operational concepts of security and of security complex.