Dismiss, in a way, from Richard's royal house (4)

I believe the answer is:

york

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

I cannot understand how the remainder of the clue works.

(Other definitions for york that I've seen before include "City and royal house" , "Northern English cathedral city" , "Home of some Mystery Plays" , "Modern Eboracum" , "Archdiocese" .)

I've seen this clue in The Guardian.

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