Safety, along with freedom, is one of the most important indicators of the quality of our lives. But it is difficult to find a word in the Russian language, which, though used just as often, includes less specific meaning. The problem is that in the light of objective expansion of the "content" of the concept of "security" its "volume" in strict accordance with the rules of logic approaches zero. If possible, a more adequate definition of such fundamental concept as "security" should be seen as return of "volume." The definition cannot be given in isolation from domain concept most closely associated with technosphere, from other concepts and relationships between concepts of technosphere security. Assessing the adequacy of the described definition (definitions) of the subject area is only possible with system approach — in connection with the other terms of terminology. Logically, the same should be addressed to the formation of scientific and technical terminology of the subject area to avoid isolated definitions, and to form separate terms and their definitions within a coherent terminological system. An example of the wrong approach to the formation of the terminology is the Introduction into the Labour Code of the Russian Federation of a new legal term "occupational hazard", which did not work in this new subject area without its content and volume. Therefore, on the example of the concept of "security" the author proposed and demonstrated the methodology of formation of terminological concept of "security" (in technosphere) based on a model called the "puzzle of concepts."