fourth vs common fraction

fourth and common fraction both are nouns.

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

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

Other hypernyms of fourth include simple fraction.

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

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