restraint vs collar

restraint and collar both are nouns.

Word	Noun	Adjective	Verb	Adverb
restraint	Yes	No	No	No
collar	Yes	No	Yes	No

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

restraint (noun)	collar (noun)
the act of controlling by restraining someone or something	the act of apprehending (especially apprehending a criminal)
a device that retards something's motion	a figurative restraint
discipline in personal and social activities	a band that fits around the neck and is usually folded over
lack of ornamentation	necklace that fits tightly around a woman's neck
a rule or condition that limits freedom	a band of leather or rope that is placed around an animal's neck as a harness or to identify it
the state of being physically constrained	the stitching that forms the rim of a shoe or boot
	a short ring fastened over a rod or shaft to limit, guide, or secure a machine part
	anything worn or placed about the neck
	(zoology) an encircling band or marking around the neck of any animal