Russian country house resembled a château, in part (5)
I believe the answer is:
'russian country house' is the definition.
(I've seen this before)
'resembled a chateau in part' is the wordplay.
'in part' indicates the answer is hidden within the clue.
'DACHA' is hidden within 'resembled a chateau'.
(Other definitions for dacha that I've seen before include "Second home in the country for Muscovites?" , "Russian second home" , "property overseas" , "Russian holiday cottage" , "Country home in Russia" .)