The nature of borrowings in the Belarussian-Lithuanian-Polish frontier area is determined by specific character of the region, where the elements of traditional Belarusian, Lithuanian dialects & Russian language as well as dialects of 'Polshchyizna kresova' are retained. One can single out lithuanisms and polonisms, a considerable part of which has been consolidated in the Belarussian language and it's functional styles and has passed all the stages of semantic adoption. Polysemants within frontier region feel on them the influence of different dialectical systems components, that is reflected in the character of their modifications. Depending on their correlation with primary sources we can distribute borrowings into 4 fundamental groups: a) borrowings with identical correlation of lexical-semantical variants (LSV) that practically copy the semantics of foreign units, b) borrowings with relations of non-coincidence (in such a case LSV of sources on Belarussian ground are lost, forgotten and therefore within semantic structures of polysemants new LSV, previously unknown, are stated), c) borrowings with relations of crossing (semantic structures of such polysemants in Belarussian dialects and sources do not coincide at all, because, as a rule, only a part of LSV, but not the whole, is adapted, so new LSV, usually of local character, appear on it's base), d) borrowings with relations of inclusion (in such a case a word in Belarussian language and it's Polish or Lithuanian equivalents differ in quantity of LSV: in one case a foreign word keeping certain meanings of original language on the Belarussian ground develops new LSV, so it increases the semantic paradigm; in the other case a borrowing in Belarussian language loses some LSV and narrows it's semantic extent). .