Colourful Dutch royal house (6)

I believe the answer is:

orange

I'm a little stuck... Click here to teach me more about this clue!

'dutch royal house' is the definition.
(I've seen this before)

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for orange that I've seen before include "Stocking-filler fruit" , "Belisha beacon colour" , "Go earn the fruit" , "Loyalist colour" , "Mandarin?" .)

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