In the methodology of science nowadays one of the main problems is the form in which the results of scientific search are presented. Thus the most important requirement is availability and clearness of the scientific information. In the hierarchy of the system of scientific knowledge, the minimum unit is the scientific concept. The study of the methods of expression of scientific concepts, their expression in terms, more broadly - in scientific texts - is the most important component of the theory of scientific cognition. The concepts and terms of social and human sciences, whose role is currently growing, require special attention. This paper analyzes the specifics of the terms and concepts of humanities and, as a result, the peculiarities of their research methodology. The application of the definition analysis of the concept as a tool for self-knowledge of science is proposed. The term and the concept of "ethnos" are considered as an example on the material of the works of Russian ethnologists, as well as in educational and political discourse.