sex chromosome vs XY

sex chromosome and XY both are nouns.

Word	Noun	Adjective	Verb	Adverb
sex chromosome	Yes	No	No	No
XY	Yes	No	No	No

As nouns, XY is a hyponym of sex chromosome; that is, XY is a word with a more specific, narrower meaning than sex chromosome:

sex chromosome: (genetics) a chromosome that determines the sex of an individual
XY: (genetics) normal complement of sex hormones in a male

Other hyponyms of sex chromosome include X chromosome, XX, XXX, XXY, XYY, Y chromosome.

sex chromosome (noun)	XY (noun)
(genetics) a chromosome that determines the sex of an individual	(genetics) normal complement of sex hormones in a male