alto rilievo vs high relief

alto rilievo and high relief both are nouns.

Word	Noun	Adjective	Verb	Adverb
alto rilievo	Yes	No	No	No
high relief	Yes	No	No	No

As nouns, alto rilievo and high relief are synonyms defined as:

alto rilievo and high relief: a sculptural relief in which forms extend out from the background to at least half their depth

Other synonyms of alto rilievo include alto relievo.

alto rilievo (noun)	high relief (noun)
a sculptural relief in which forms extend out from the background to at least half their depth	a sculptural relief in which forms extend out from the background to at least half their depth