Death is the permanent termination of the biological functions that sustain a living organism. Phenomena which commonly bring about death include old age, predation, malnutrition, disease, and accidents or trauma resulting in terminal injury.
(From the Wikipedia article on Death)
In teachings at various points on my Buddhist path, people have pointed out that the phrase "Old Age, Sickness and Death" doesn't mean just the "end of life" as we commonly would (want to?) think it does. "Old Age begins at birth," one teacher noted - the second you are born, you begin to approach Death. Sickness is also a life-long deterioration. We are impermanent, that's part of the womb-to-tomb contract we sign in blood upon entering this world.
