mezzo-rilievo vs relievo

mezzo-rilievo and relievo both are nouns.

Word	Noun	Adjective	Verb	Adverb
mezzo-rilievo	Yes	No	No	No
relievo	Yes	No	No	No

As nouns, relievo is a hypernym of mezzo-rilievo; that is, relievo is a word with a broader meaning than mezzo-rilievo:

mezzo-rilievo: a sculptural relief between low relief and high relief
relievo: sculpture consisting of shapes carved on a surface so as to stand out from the surrounding background

Other hypernyms of mezzo-rilievo include embossment, relief, rilievo, sculptural relief.

mezzo-rilievo (noun)	relievo (noun)
a sculptural relief between low relief and high relief	sculpture consisting of shapes carved on a surface so as to stand out from the surrounding background