Abstract: Subject. The multi-component structure of concept NOBILITY / БЛАГОРОДСТВО in the English and Russian languages characterized by the presence of various groups of cognitive signs of the concept is the evidence of its importance in the culture of these nations. The study aims to define the nominative density of the concept NOBILITY / БЛАГОРОДСТВО in the English and Russian languages by the comparative analysis in diachrony makes it possible to determine the importance of the concept in the culture of the English and Russian ethnic groups and to identify the differences in the above mentioned linguistic cultures.Methods. The data for the study was obtained from the texts of contemporary English and Russian fiction writers with reference to the etymological and explanatory English and Russian dictionaries data. Text selection was carried out by continuous sampling. A wide range of methods and techniques for studying and modeling the concept was used: the method of etymological analysis, the method of analysis of dictionary definitions, method of semantic-component analysis, technique of continuous sampling, technique of contextual analysis method of linguistic description and observation method diachronic studies, comparative method, the method of statistical calculations. Topicality. Comparative analysis of the concept NOBILITY / БЛАГОРОДСТВО in diachrony revealed differences in its nominative density, which gives us the opportunity to talk about the specifics of the English and Russian national picture of the world and priority of certain concepts for the native speakers of these languages.Conclusions. The highest nominative density in the English linguistic culture has a cognitive feature of the concept that expresses high origin, belonging to a upper social class which is present in all synchronous periods of texts, whereas, in all investigated periods of Russian linguistic culture high frequency has a cognitive sign of the concept that expresses the high moral qualities and this indicates cultural differences in data of ethnic groups. The cognitive feature of the concept "high origin, class" in the Russian sphere of concept was erased with time, losing its cultural significance for the Russian language consciousness. In both nominative spheres of the concept the lowest density characterizes the cognitive features of external manifestations of nobility.