mor·​tal·​i·​ty | \ mȯr-ˈta-lə-tē How to pronounce mortality (audio) \

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

Anorexia has one of the highest mortality rates of any psychiatric disorder, and scientists are still perplexed by its causes. Tanya Lewis, Scientific American, "Anorexia May Be Linked to Metabolism, a Genetic Analysis Suggests," 15 July 2019 Lo and her colleagues took those goals and ran with them, combining an array of temperature and mortality data to try to imagine life and death when the U.S. is in a hotter world. Emily Baumgaertner,, "Hitting Paris climate goals would save 759 lives in L.A. during huge heat wave, study finds," 5 June 2019 This analysis produces a number roughly in line with the mortality data. John Timmer, Ars Technica, "Target of first human gene editing cuts life expectancy short," 5 June 2019 Since 2017, the skeletal remains of more than 40 people have been found in Cabeza Prieta, according to migrant mortality data collected with the help of Pima County’s medical examiner office. Jacob Gershman, WSJ, "Aid for Immigrants on Desert Trek Stirs Religion-Freedom Fight," 6 Dec. 2018 Up until Friday, the agency had declined to release finalized mortality data while its investigators work with researchers from George Washington University to review territory archives. Arelis R. Hernandez,, "New Puerto Rico data shows deaths increased by 1,400 after Hurricane Maria," 1 June 2018 The scientists then followed the women for an average of 2.3 years to determine their mortality data. Karen D'souza, The Seattle Times, "To live longer, clean house or take your dog for a walk," 21 Jan. 2018 For the study, researchers looked at temperature and heat mortality data from 15 U.S. cities between 1987 and 2000. Jason Daley, Smithsonian, "Heat Waves Could Kill Thousands of People in U.S. Cities If Climate Goals Aren’t Met," 17 Aug. 2015 Their buoyancy means their mortality rate is low, but the position of some of the ants suggests that these soldiers, like the demodogs, may die protecting their queen. Ashley Strickland, CNN, "The weird Upside Down science behind 'Stranger Things'," 4 July 2019

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

22 Jul 2019

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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 How to pronounce mortality (audio) \
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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something desired as essential

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