In the modern world, which is characterised by migration processes, ethnic and cultural mixing, the interest of representatives of various fields of knowledge to the category of ethnicity, ethnic processes, their historical, cultural, philosophical and linguistic component is growing. In this regard, the work is devoted to studying the dynamics of representations of ethnicity in different types of discursive practices and identifying the specifics of conceptualisation of ethnicity in English-speaking society in the context of ideological, socio-economic and socio-cultural transformations of the second half of the 20th – early 21st century. The relevance of the study is due to the inclusion of the dynamics of language development and change in such areas of modern linguistics as ethnolinguistics, linguocultural studies and discourse analysis, as well as growing interest in the evolution of language, lexical structure of English and changes in the English world picture with the development of ethnic culture, the synthesis of language modifications in the context of global socio-cultural transformations. The following methods were used in the work: definition analysis; comparative analysis; quantitative analysis; analysis-discourse; hypothetical-deductive method; generalisation; systematisation. The research methods used in the article made it possible to substantiate the principles of material selection for studying the dynamics of ethnic representations in English dictionaries; to reveal the concepts of ethnic stereotype and ethnonym-nickname as ways of stereotyping; to characterise the concept of political correctness as relevant for the study of linguistic construction of ethnicity. The dynamics of the representation of ethnicity in the lexicographic discourse on the material of British dictionaries of two times cross-sections (mid-20th century and modern latest edition) in the context of socio-cultural transformations were analysed. The practical value of the work is that the obtained results contribute to a fuller understanding of the English-language picture of the world, deepen scientific ideas about the interaction of ideology, language, culture.