What is Mortality Definition: Mortality? Mor·tal·i·ty Mortality is the state of death of a living organism. The term mortal refers to the idea that we are not forever alive. Mortality is sometimes confused with morbidity. Updated on January 4, 2019 Was this article helpful? Yes No Related Articles Gomco Clamp-Circumcision surgical device Exogenous Ketones Understand Fasting-Fasting Defined Ketones and ways to measure ketones Ketosis: What is Ketosis all about? Morbitity