neckband vs necklace

neckband and necklace both are nouns.

Word	Noun	Adjective	Verb	Adverb
neckband	Yes	No	No	No
necklace	Yes	No	No	No

As nouns, necklace is a hypernym of neckband; that is, necklace is a word with a broader meaning than neckband:

neckband: necklace that fits tightly around a woman's neck
necklace: jewelry consisting of a cord or chain (often bearing gems) worn about the neck as an ornament (especially by women)

neckband (noun)	necklace (noun)
a band that fits around the neck and is usually folded over	jewelry consisting of a cord or chain (often bearing gems) worn about the neck as an ornament (especially by women)
necklace that fits tightly around a woman's neck
a band around the collar of a garment