mortality

noun

mor·​tal·​i·​ty mȯr-ˈta-lə-tē 

1

: the quality or state of being mortal

Her husband's death reminded her of her own mortality.

2

: the death of large numbers (as of people or animals)

trying to reduce infant mortality

3

archaic : death

4

: the human race

… that natural extinction to which all mortality is subject …

—Thomas Paine

5

a

: the number of deaths in a population during a given time or place : the proportion of deaths to population : mortality rate

The mortality among the infected mounted daily.

b

: the number lost or the rate of loss or failure

the mortality rate of small businesses

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Thoughts on Mortality

Young people tend to assume they will never die, but a person's sense of his or her mortality generally increases year by year, and often increases greatly after a serious accident or illness. Still, many people refuse to change behaviors that would improve their chances of living into old age. Mortality rates are calculated by government agencies, insurance companies, and medical researchers. Infant mortality rates (the rate at which infants die in childbirth) provide a good indicator of a country's overall health; in recent years, the rates in countries like Iceland, Singapore, and Japan have been much better than in the U.S.

Examples of mortality in a Sentence

a leading cause of mortality

Recent Examples on the Web

According to Borne, their outing aspired to highlight ongoing research into why babies are born prematurely, as premature birth is the leading cause of childhood mortality worldwide, and to accelerate advancements for safer pregnancies and healthier births. —Janine Henni, PEOPLE, 11 Nov. 2025

Young and Solomon Hsiang, a colleague at Stanford, tried to link state-by-state mortality data to five hundred tropical cyclones since 1930. —Clayton Dalton, New Yorker, 11 Nov. 2025

According to a meta-analysis published in PLOS One, low skeletal muscle mass was associated with a 57% higher risk of all-cause mortality than those with normal levels. —Alexa Mikhail, Flow Space, 10 Nov. 2025

However, fruit-bearing varieties have become invasive in natural habitats and nandina berry consumption has been linked to bird mortality in at least one instance. —Kim Toscano, Southern Living, 6 Nov. 2025

Word History

Etymology

Middle English mortalite, borrowed from Anglo-French mortalité, mortelté, borrowed from Latin mortālitāt-, mortālitās, from mortālis "subject to death, mortal entry 1" + -itāt-, -itās -ity

First Known Use

15th century, in the meaning defined at sense 1

Phrases Containing mortality

• infant mortality
• mortality rate
• mortality table

Rhymes for mortality

• banality
• bestiality
• brutality
• carnality
• centrality
• chirality
• duality
• fatality
• finality
• formality
• frugality
• legality

Kids Definition

mortality

noun

mor·​tal·​i·​ty mȯr-ˈtal-ət-ē 

plural mortalities

1

: the quality or state of being mortal

2

: the death of large numbers (as of animals or people)

3

a

: the number of deaths in a given time or place

b

: the ratio of deaths occurring in a certain time in a given population to the number of individuals in the population

Medical Definition

mortality

noun

mor·​tal·​i·​ty mȯr-ˈtal-ət-ē 

plural mortalities

1

: the quality or state of being mortal

2

: the number of deaths in a population during a given time or place : the proportion of deaths to population : mortality rate compare morbidity sense 2