Abstract
The study deals with a cryptical place in The Tale of Igor's Campaign, the phrase bebrjan rukav which is mentioned in the Princess Yaroslavna's monologue lament. A presumptive adjective bebrjan, traditionally to be derived from the zoonym bebr ("beaver"), does not find any reliable parallels in the Old East Slavic texts and is very difficult to be reconstructed on the basis of the supposed semantic equivalents that appear only sporadically in a few translations from Greek.
Even then, semantic contradictions would become apparent, supporting the (assumption) of the form bebrjan as a result of the copyist's mistake, who interpreted the incomprehensible original phrase, judged by the usage of the word beber in The Story of Ahikar, which he had copied before (odѣch i bebrom; odѣvša a v beber).