multiple sclerosis vs sclerosis

multiple sclerosis and sclerosis both are nouns.

Word	Noun	Adjective	Verb	Adverb
multiple sclerosis	Yes	No	No	No
sclerosis	Yes	No	No	No

As nouns, sclerosis is a hypernym of multiple sclerosis; that is, sclerosis is a word with a broader meaning than multiple sclerosis:

multiple sclerosis: a chronic progressive nervous disorder involving loss of myelin sheath around certain nerve fibers
sclerosis: any pathological hardening or thickening of tissue

Other hypernyms of multiple sclerosis include degenerative disorder, induration, autoimmune disease, autoimmune disorder.

multiple sclerosis (noun)	sclerosis (noun)
a chronic progressive nervous disorder involving loss of myelin sheath around certain nerve fibers	any pathological hardening or thickening of tissue