bow tie vs necktie

bow tie and necktie both are nouns.

Word	Noun	Adjective	Verb	Adverb
bow tie	Yes	No	No	No
necktie	Yes	No	No	No

As nouns, necktie is a hypernym of bow tie; that is, necktie is a word with a broader meaning than bow tie:

bow tie: a man's tie that ties in a bow
necktie: neckwear consisting of a long narrow piece of material worn (mostly by men) under a collar and tied in knot at the front

Other hypernyms of bow tie include tie.

bow tie (noun)	necktie (noun)
a man's tie that ties in a bow	neckwear consisting of a long narrow piece of material worn (mostly by men) under a collar and tied in knot at the front