fourth vs simple fraction

fourth and simple fraction both are nouns.

Word	Noun	Adjective	Verb	Adverb
fourth	Yes	Yes	No	Yes
simple fraction	Yes	No	No	No

As nouns, simple fraction is a hypernym of fourth; that is, simple fraction is a word with a broader meaning than fourth:

Other hypernyms of fourth include common fraction.

fourth (noun)	simple fraction (noun)
the musical interval between one note and another four notes away from it	the quotient of two integers
one of four equal parts
following the third position; number four in a countable series

fourth (adjective)	simple fraction (adjective)
coming next after the third and just before the fifth in position or time or degree or magnitude

fourth (adverb)	simple fraction (adverb)
in the fourth place