Group of relatives in the house band (6,6)
I believe the answer is:
family circle
'group of relatives in the house band' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe you can see an association between them that I don't see?
'in the house band' is the wordplay.
'in the house' becomes 'family' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'band' becomes 'circle' ('circle' can be a synonym of 'band').
'family'+'circle'='FAMILY CIRCLE'
Can you help me to learn more?
(Other definitions for family circle that I've seen before include "Kith and kin" , "Close kin - cheap theatre seats (US)" , "all my relations" , "Group composed of one's relatives" , "Collectively" .)