topknot vs headgear

topknot and headgear both are nouns.

Word	Noun	Adjective	Verb	Adverb
topknot	Yes	No	No	No
headgear	Yes	No	No	No

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

topknot: headdress consisting of a decorative ribbon or bow worn in the hair
headgear: clothing for the head

Other hypernyms of topknot include headdress.

topknot (noun)	headgear (noun)
showy crest or knot of hair or feathers	clothing for the head
headdress consisting of a decorative ribbon or bow worn in the hair	stable gear consisting of any part of a harness that fits about the horse's head
	the hoist at the pithead of a mine