pectoral medallion vs adornment

pectoral medallion and adornment both are nouns.

Word	Noun	Adjective	Verb	Adverb
pectoral medallion	Yes	No	No	No
adornment	Yes	No	No	No

As nouns, adornment is a hypernym of pectoral medallion; that is, adornment is a word with a broader meaning than pectoral medallion:

pectoral medallion: an adornment worn on the chest or breast
adornment: a decoration of color or interest that is added to relieve plainness

pectoral medallion (noun)	adornment (noun)
an adornment worn on the chest or breast	the action of decorating yourself with something colorful and interesting
	a decoration of color or interest that is added to relieve plainness