sibling vs quin

sibling and quin both are nouns.

Word	Noun	Adjective	Verb	Adverb
sibling	Yes	No	No	No
quin	Yes	No	No	No

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

Other hyponyms of sibling include half blood, quad, quadruplet, quint, quintuplet, triplet, twin.

sibling (noun)	quin (noun)
a person's brother or sister	one of five children born at the same time from the same pregnancy