Many thanks September donors. October donations open to all users. - Donate here
From Citizendium, the Citizens' Compendium
In epidemiology, morbidity is the incidence of illness, due to a common cause, in a specified population over a specified period of time. Mortality is the incidence of fatal illness due to the same cause in the same population.
It is most commonly stated numerically, as a rate, but can be used generically, as in speaking of the morbidity due to some common source.