The King has jewelled items (6)
I believe the answer is:
crowns
'jewelled items' is the definition.
The answer and definition can be both man-made objects as well as being plural nouns.
Perhaps they are linked in a way I don't understand?
'the king has' is the wordplay.
'the king' becomes 'CR' (short for Carolus Rex, King Charles in Latin).
'has' becomes 'owns' ('own' can be a synonym of 'have').
'cr'+'owns'='CROWNS'
Can you help me to learn more?
(Other definitions for crowns that I've seen before include "Tops of heads - tops of teeth" , "emblems of kingship" , "Symbols of monarchy" , "At least ten shillings" , "caps" .)