American rotter holding Henry back in Russian cottage (5)
I believe the answer is:
dacha
'russian cottage' is the definition.
(I've seen this in another clue)
'american rotter holding henry back' is the wordplay.
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'rotter' becomes 'cad' (a cad is a dishonourable person).
'holding' means one lot of letters goes inside another.
'henry' becomes 'H' (symbol for the unit of electrical inductance).
'back' shows that the letters should be reversed in order.
'a'+'cad'='acad'
'acad' enclosing 'h' is 'ahcad'.
'ahcad' back-to-front is 'DACHA'.
'in' acts as a link.
(Other definitions for dacha that I've seen before include "Russian second home" , "Russian country home" , "Russian retreat" , "summer house" , "Russian villa" .)