ordinal vs billionth

ordinal and billionth both are nouns.

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

ordinal (noun)	billionth (noun)
the number designating place in an ordered sequence	one part in a billion equal parts
	position 1,000,000,000 in a countable series of things

ordinal (adjective)	billionth (adjective)
being or denoting a numerical order in a series	the ordinal number of one billion in counting order
of or relating to a taxonomic order