дебри

Inherited from Old East Slavic дъбрь (dŭbrĭ) : дьбрь (dĭbrĭ), from Proto-Slavic *dьbrь (“valley, ravine”), from Proto-Balto-Slavic *dubris, from Proto-Indo-European *dʰubr-, from *dʰewbʰ- (“deep”).

• IPA^(key): [ˈdʲebrʲɪ]

де́бри • (débri) m inan pl (genitive де́брей, plural only)

1. thickets, jungle, wilderness, wilds, bush
2. (figuratively) maze, labyrinth

   запу́таться в де́брях ― zapútatʹsja v débrjax ― to be lost in the maze (of something), to get bogged down (in a difficult problem)

• Брянск (Brjansk) (< Дьбрѧньскъ (Dĭbręnĭskŭ))

• Vasmer, Max (1964–1973) “дебрь”, in Oleg Trubachyov, transl., Этимологический словарь русского языка [Etymological Dictionary of the Russian Language] (in Russian), Moscow: Progress
• Chernykh, P. Ja. (1993) “дебри”, in Историко-этимологический словарь русского языка [Historical-Etymological Dictionary of the Russian Language] (in Russian), 3rd edition, volumes 1 (а – пантомима), Moscow: Russian Lang., →ISBN, page 234