Jewelled head ornament (5)
I believe the answer is:
tiara
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">jewelled head ornament</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for tiara that I've seen before include "Top decoration" , "Crescent-shaped headdrsss or Pope's diadem" , "Jewelled headband" , "Type of diadem" , "Jewelled head wear" .)