fourth vs ordinal

fourth and ordinal both are nouns.

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

fourth (noun)	ordinal (noun)
the musical interval between one note and another four notes away from it	the number designating place in an ordered sequence
one of four equal parts
following the third position; number four in a countable series

fourth (adjective)	ordinal (adjective)
coming next after the third and just before the fifth in position or time or degree or magnitude	being or denoting a numerical order in a series
	of or relating to a taxonomic order

fourth (adverb)	ordinal (adverb)
in the fourth place