eighth vs ordinal

eighth and ordinal both are nouns.

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

eighth (noun)	ordinal (noun)
one part in eight equal parts	the number designating place in an ordered sequence
position eight in a countable series of things

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