cheese fondue vs fondu

cheese fondue and fondu both are nouns.

Word	Noun	Adjective	Verb	Adverb
cheese fondue	Yes	No	No	No
fondu	Yes	No	No	No

As nouns, fondu is a hypernym of cheese fondue; that is, fondu is a word with a broader meaning than cheese fondue:

cheese fondue: fondue made of cheese melted in wine for dipping bread and sometimes fruits
fondu: hot cheese or chocolate melted to the consistency of a sauce into which bread or fruits are dipped

Other hypernyms of cheese fondue include fondue.

cheese fondue (noun)	fondu (noun)
fondue made of cheese melted in wine for dipping bread and sometimes fruits	hot cheese or chocolate melted to the consistency of a sauce into which bread or fruits are dipped
	cubes of meat or seafood cooked in hot oil and then dipped in any of various sauces