necklace vs dog collar

necklace and dog collar both are nouns.

Word	Noun	Adjective	Verb	Adverb
necklace	Yes	No	No	No
dog collar	Yes	No	No	No

As nouns, dog collar is a hyponym of necklace; that is, dog collar is a word with a more specific, narrower meaning than necklace:

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

Other hyponyms of necklace include chain, strand, string, chain, choker, collar, neckband.

necklace (noun)	dog collar (noun)
jewelry consisting of a cord or chain (often bearing gems) worn about the neck as an ornament (especially by women)	a collar for a dog
	a stiff white collar with no opening in the front; a distinctive symbol of the clergy
	necklace that fits tightly around a woman's neck