hardening of the arteries vs coronary-artery disease

hardening of the arteries and coronary-artery disease both are nouns.

Word	Noun	Adjective	Verb	Adverb
hardening of the arteries	Yes	No	No	No
coronary-artery disease	Yes	No	No	No

As nouns, hardening of the arteries and coronary-artery disease are synonyms defined as:

hardening of the arteries and coronary-artery disease: sclerosis of the arterial walls

Other synonyms of hardening of the arteries include arterial sclerosis, arteriosclerosis, induration of the arteries.

hardening of the arteries (noun)	coronary-artery disease (noun)
sclerosis of the arterial walls	sclerosis of the arterial walls