Death is the permanent, irreversible cessation of all biological functions that sustain a living organism. Brain death is sometimes used as a legal definition of death. The remains of a previously living organism normally begin to decompose shortly after death. Death is an inevitable, universal process that eventually occurs in all living organisms.
Death is generally applied to whole organisms; the similar process seen in individual components of a living organism, such as cells or tissues, is necrosis. Something that is not considered a living organism, such as a virus, can be physically destroyed but is not said to die.
As of the early 21st century, over 150,000 humans die each day.
Many cultures and religions have the idea of an afterlife, and also may hold the idea of judgement of good and bad deeds in one's life (Heaven, Hell, Karma).