myonecrosis vs necrosis

myonecrosis and necrosis both are nouns.

Word	Noun	Adjective	Verb	Adverb
myonecrosis	Yes	No	No	No
necrosis	Yes	No	No	No

As nouns, necrosis is a hypernym of myonecrosis; that is, necrosis is a word with a broader meaning than myonecrosis:

myonecrosis: localized death of muscle cell fibers
necrosis: the localized death of living cells (as from infection or the interruption of blood supply)

Other hypernyms of myonecrosis include gangrene, mortification, sphacelus.

myonecrosis (noun)	necrosis (noun)
localized death of muscle cell fibers	the localized death of living cells (as from infection or the interruption of blood supply)