ordinal vs fifteenth

ordinal and fifteenth both are nouns.

Word	Noun	Adjective	Verb	Adverb
ordinal	Yes	Yes	No	No
fifteenth	Yes	Yes	No	No

ordinal (noun)	fifteenth (noun)
the number designating place in an ordered sequence	position 15 in a countable series of things

ordinal (adjective)	fifteenth (adjective)
being or denoting a numerical order in a series	coming next after the fourteenth and just before the sixteenth in position
of or relating to a taxonomic order