ENThe aim of this article is to highlight theoretical and methodological aspects of the notion of Borderlands, to indicate heteronymous quality of this notion and to point to its lingual identyfications based on the realities of Eastern Borderlands of Poland. To achieve this purpose it is necessary to present the conceptual and terminological structure of the idea of Borderlands and theoretical foundations of multilingualism. These notions must be correlated with such data concerning Eastern Borderlands as ethno- and socio-lingual situation, system features of the language and its variations, and such distinguishing features as linguonyms, stereotypes, traces of Borderlands in literature and Borderlands characteristics of language in lexicographic works on Polish vocabulary as well as words- symbols of culture.