The insignia of royalty (7)
I believe the answer is:
regalia
'the insignia of royalty' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for regalia that I've seen before include "Ceremonial trimmings of high office" , "Crown jewels" , "Royal accoutrements" , "Finery" , "Royal trappings" .)