basso relievo vs bas relief

basso relievo and bas relief both are nouns.

Word	Noun	Adjective	Verb	Adverb
basso relievo	Yes	No	No	No
bas relief	Yes	No	No	No

As nouns, basso relievo and bas relief are synonyms defined as:

basso relievo and bas relief: a sculptural relief in which forms extend only slightly from the background; no figures are undercut

Other synonyms of basso relievo include basso rilievo, low relief.

basso relievo (noun)	bas relief (noun)
a sculptural relief in which forms extend only slightly from the background; no figures are undercut	a sculptural relief in which forms extend only slightly from the background; no figures are undercut