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

The maternal mortality rate has more than doubled in the U.S. over the last 30 years, despite medical advances, often due to insufficient health care. Julie Mazziotta,, "OB-GYN Accused of Negligence After Mom Dies Hours After Giving Birth," 27 Aug. 2019 The rate of hospitalization is about one in five, mostly owing to pneumonia, and the mortality rate is about one in a thousand. Nick Paumgarten, The New Yorker, "The Message of Measles," 26 Aug. 2019 According to the study, the two countries that saw the largest increase in mortality rates as air pollution levels went up are Australia and Brazil. Fox News, "Breathing polluted air is deadlier than previously believed, new study claims," 23 Aug. 2019 Invest more money In 2017, about $100 million was spent on suicide research, according to the National Institutes of Health, compared to $690 million on breast cancer, or $2 billion on Alzheimer’s, despite lower mortality rates. Lizz Schumer, Woman's Day, "Is Suicide Preventable? Experts Weigh In," 22 Aug. 2019 Trees and other plants may be able to survive these stresses for one year, but longer stretches could lead to increases in forest mortality. Adrienne Marshall, The Conversation, "Climate change will mean more multiyear snow droughts in the West," 8 Aug. 2019 Their research shows a steady increase in mortality and orca pregnancy failure due to lack of adequate food. Lynda V. Mapes, The Seattle Times, "Orca survival may be impossible without Lower Snake River dam removal, scientists say," 15 Oct. 2018 These include transport conditions, mortality rate, tattooing numbers and the removal of any sign of selfhood, heritage, customs, and cultural identity. Wesley J. Smith, National Review, "Chimpanzee Liberation? Why Animal Rights and Human Rights Cannot Coexist," 15 Aug. 2019 If treated early, mortality rates drastically dropped, to 6 percent with REGN-EB3 and 11 percent with mAb114. Catherine Kim, Vox, "Vox Sentences: One step closer to an Ebola cure," 15 Aug. 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

2 Sep 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

What made you want to look up mortality? Please tell us where you read or heard it (including the quote, if possible).


readily or continually undergoing change

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