rabbit warren [noun] [C] - a series of connecting underground passages and holes in which rabbits live (esp. disapproving) A warren can also be a very crowded and confusing building or part of a city in which it is easy to get lost.They live on a great concrete warren of a housing estate.
WARREN
Meaning of WARREN in English
Cambridge English vocab. Кембриджский английский словарь. 2012