yttrium vs Y

yttrium and Y both are nouns.

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

As nouns, yttrium and Y are synonyms defined as:

yttrium and Y: a silvery metallic element that is common in rare-earth minerals; used in magnesium and aluminum alloys

Other synonyms of yttrium include atomic number 39.

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