In any special human activity, you can distinguish between a practical and theoretical approach to research. This article highlights the problems of special vocabulary of a certain sublanguage, approaches that allow identifying the inventory of linguistic signs. Discusses the process only semiotically complex entities of scientific-technical terminology, which is a simple design, the Exhibitor, for example, the construction "adjective plus noun", or in the case of the realization of a certain structural-semantic model, in which values of components, as their choice, to a certain extent due to the nature of the model itself. In addition, linguistic systems and subsystems are noted that cover transitional elements  are at various stages of inclusion or dropout in a particular system of linguistic units. The article also offers a synchro-semiotic analysis of language signs as a step in the diachronic process of sign formation of scientific and technical terminology. In terms of language synchrony, the associative relationship between the intrinsic and special meaning of a complex sign, in principle, has the same conditional, arbitrary character as the relationship between the meanings of individual components of the intangible form of the sign. The result of the proposed analysis of complex formations represents the form of analytical expression of concepts and functioning in scientific and technical speech in parallel with the terms. It is argued that an understanding of semiotically complex formations and the motivation of terms helps the correct use of the concept in speech.