twenty-eighth vs ordinal

twenty-eighth is not a noun while ordinal is a noun.

Word	Noun	Adjective	Verb	Adverb
twenty-eighth	No	Yes	No	No
ordinal	Yes	Yes	No	No

twenty-eighth (noun)	ordinal (noun)
	the number designating place in an ordered sequence

twenty-eighth (adjective)	ordinal (adjective)
coming next after the twenty-seventh in position	being or denoting a numerical order in a series
	of or relating to a taxonomic order