Piece of fruit in William III's house (6)
I believe the answer is:
orange
This might be a double definition.
'piece of fruit' is the first definition.
'orange' can be an answer for 'fruit' (orange is a kind of fruit). I am not sure about the 'piece of' bit.
'william iii's house' is the second definition.
(as in William of Orange)
'in' is the link.
Can you help me to learn more?
(Other definitions for orange that I've seen before include "Colour of Northern Ireland unionism" , "Go near (anag) - fruit" , "Colour of an onager?" , "soft drink?" , "juicy snack" .)