Remaining one in residence made for two (8)
I believe the answer is:
residual
'remaining' is the definition.
(thesaurus)
'one in residence made for two' is the wordplay.
'one' becomes 'i' (Roman numeral).
'in' indicates putting letters inside.
'residence' becomes 'res'.
'made for two' becomes 'dual' (I can't justify this - if you can you should give a lot more credence to this answer).
'res'+'dual'='resdual'
'i' going within 'resdual' is 'RESIDUAL'.
Can you help me to learn more?
(Other definitions for residual that I've seen before include "Remaining at the end" , "Remaining; repeat royalty" , "Leftover; repeat royalty" , "Left over as a remainder" , "'Remaining, left over (8)'" .)