Abstract
The relationship between specialized phrases and science is bidirectional: on the one hand, the professional lexicon is a reflection of science, being subject to permanent changes, on the other hand, concepts are a reflection of the evolution of human knowledge. The objective of our research is to study the process of formation of poly-lexical phrases - within the lexicon - and their transition into the specialized lexicon. Analysis, comparison, and descriptive-linguistic methods are some of the research methods used. The general conclusion that emerges is that the terminological phrase is a particularly productive process in the professional language.