noun (n)

• the quality or state of being mortal(noun.attribute)

  Antonym:
  immortality
  

  source: wordnet30
• the ratio of deaths in an area to the population of that area; expressed per 1000 per year(noun.time)

  Synonym:
  death rate, deathrate, fatality rate, mortality rate
  

  source: wordnet30
• The condition or quality of being mortal; subjection to death or to the necessity of dying.(noun)

  source: webster1913