y vs Y

y and Y both are nouns.

Word	Noun	Adjective	Verb	Adverb
y	Yes	No	No	No
Y	Yes	No	No	No

As nouns, y and Y are synonyms defined as:

Other synonyms of y include wye.

y (noun)	Y (noun)
the 25th letter of the Roman alphabet	the 25th letter of the Roman alphabet
	a silvery metallic element that is common in rare-earth minerals; used in magnesium and aluminum alloys