mor·​tal·​i·​ty | \mȯr-ˈta-lə-tē \

Definition of mortality 

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

5a : the number of deaths in a given time or place The mortality among the infected mounted daily.

b : the proportion of deaths to population a brain infection with a mortality rate of about 30 percent— Jane E. Brody

c : 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

After two hours or so, the students, some facing personal issues of mortality involving friends and family members, led out, exhausted but inspired. Bob Morris, Town & Country, "How College Courses on Happiness and Humiliation Because the Hottest Trend on Campus," 10 July 2018 Pennsylvania’s rate of firearms mortality is higher than in neighboring states and slightly higher than the national average. Ian Haydon,, "Kids and guns: Study finds urban-rural divide that changes with age," 9 July 2018 And then, from this most specific, painful, awful experience, Weems zooms out, back into the universal fact of mortality. Alexis C. Madrigal, The Atlantic, "How Do You Measure a Country?," 1 July 2018 Moving on the ground is more dangerous than moving in trees, so house wrens have higher chances of mortality. National Geographic, "Birds That Leave Nest Too Late Can Endanger Their Families," 25 June 2018 But Hayes isn’t describing canonical melancholy, the pined-for vision of mortality that poets sometimes indulge in. Dan Chiasson, The New Yorker, "The Politics and Play of Terrance Hayes," 24 June 2018 In a trial run of this new software at two U.S. hospitals, the Google AI was 95 percent and 93 percent accurate in its predictions of patient mortality. Avery Thompson, Popular Mechanics, "New Google AI Calculates the Odds You'll Survive a Hospital Stay," 19 June 2018 These accompanying objects lend the composition a mildly melancholic sense of mortality. Mike Giuliano, Howard County Times, "From the studio to the gallery," 8 June 2018 But the researchers added a simulation in which the depth and mass of fish were tied to the rate of mortality by fishing. Diana Gitig, Ars Technica, "Ecological “law” turns out to just be the result of us fishing," 8 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'mortality.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of mortality

15th century, in the meaning defined at sense 1

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Statistics for mortality

Last Updated

28 Oct 2018

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The first known use of mortality was in the 15th century

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English Language Learners Definition of mortality

: the quality or state of being a person or thing that is alive and therefore certain to die : the quality or state of being mortal

: the death of a person, animal, etc.

: the number of deaths that occur in a particular time or place


mor·​tal·​i·​ty | \mȯr-ˈtal-ət-ē \
plural mortalities

Medical Definition of mortality 

1 : the quality or state of being mortal

2a : the number of deaths in a given time or place

b : the proportion of deaths to population : death rate

called also mortality rate

— compare fertility sense 2, morbidity sense 2

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Comments on mortality

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