The Proto-Indo-European word *mr̥tís
Word *mr̥tís
Meaning death
See also Proto-Indo-European: *mer- ‘to die’
Synonyms *nek̂s, *mr̥tóm, *móros

Comments
Mallory J.P. and Adams D. (2006)

Other words that might be of interest
*hₐóyus ‘vital force, life, age of vigour’, *wel- ‘die’, *mr̥tós ‘dead, mortal’, *mórtos ‘person, mortal, man’