Semi-circular jewelled headdress (5)
I believe the answer is:
tiara
(Other definitions for tiara that I've seen before include "Great delight" , "High diadem" , "Top decoration" , "Small crown" , "It bejewels" .)
I believe the answer is:
tiara
(Other definitions for tiara that I've seen before include "Great delight" , "High diadem" , "Top decoration" , "Small crown" , "It bejewels" .)