Dutch royal house — fruit (6)
I believe the answer is:
orange
This clue is a double definition.
'dutch royal house' is the first definition.
(I've seen this before)
'fruit' is the second definition.
(orange is a kind of fruit)
(Other definitions for orange that I've seen before include "Colour of an onager?" , "Fruit - part of the spectrum" , "Princely house" , "Round fruit (6)" , "Colour between red and yellow" .)