Dancing girl lay behind house, the object of desire (4,5)
I believe the answer is:
holy grail
'the object of desire' is the definition.
I can't judge whether this defines the answer.
'dancing girl lay behind house' is the wordplay.
'dancing' is an anagram indicator.
'behind' means one lot of letters go next to another.
'house' becomes 'ho' (abbreviation for house).
'girl'+'lay'='girllay'
'girllay' with letters rearranged gives 'lygrail'.
'lygrail' put after 'ho' is 'HOLY GRAIL'.
Can you help me to learn more?
(Other definitions for holy grail that I've seen before include "Legendary cup used by Jesus at Last Supper" , "A cherished ambition" , "Go, Hillary! (anag) -- chalice used by Jesus at the Last Supper" , "Something eagerly sought" , "Object of search" .)