bas relief vs embossment

bas relief and embossment both are nouns.

Word	Noun	Adjective	Verb	Adverb
bas relief	Yes	No	No	No
embossment	Yes	No	No	No

As nouns, embossment is a hypernym of bas relief; that is, embossment is a word with a broader meaning than bas relief:

bas relief: a sculptural relief in which forms extend only slightly from the background; no figures are undercut
embossment: sculpture consisting of shapes carved on a surface so as to stand out from the surrounding background

Other hypernyms of bas relief include relief, relievo, rilievo, sculptural relief.

bas relief (noun)	embossment (noun)
a sculptural relief in which forms extend only slightly from the background; no figures are undercut	sculpture consisting of shapes carved on a surface so as to stand out from the surrounding background
	an impression produced by pressure or printing