jewelled headdress vs headgear

jewelled headdress and headgear both are nouns.

Word	Noun	Adjective	Verb	Adverb
jewelled headdress	Yes	No	No	No
headgear	Yes	No	No	No

As nouns, headgear is a hypernym of jewelled headdress; that is, headgear is a word with a broader meaning than jewelled headdress:

Other hypernyms of jewelled headdress include headdress.

jewelled headdress (noun)	headgear (noun)
a headdress adorned with jewels	clothing for the head
	stable gear consisting of any part of a harness that fits about the horse's head
	the hoist at the pithead of a mine