Jewelled headdress (5)
I believe the answer is:
tiara
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">jewelled headdress</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that tiara is a type of jewelled headdress)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for tiara that I've seen before include "Small crown" , "special headgear" , "Pope's triple-tiered crown" , "Jewelled crescent-shaped headdress" , "Women's head ornament" .)