mortality vs fatality rate

mortality and fatality rate both are nouns.

Word	Noun	Adjective	Verb	Adverb
mortality	Yes	No	No	No
fatality rate	Yes	No	No	No

As nouns, mortality and fatality rate are synonyms defined as:

mortality and fatality rate: the ratio of deaths in an area to the population of that area; expressed per 1000 per year

Other synonyms of mortality include death rate, deathrate, mortality rate.

mortality (noun)	fatality rate (noun)
the quality or state of being mortal	the ratio of deaths in an area to the population of that area; expressed per 1000 per year
the ratio of deaths in an area to the population of that area; expressed per 1000 per year