There are two completely different meanings to death. The first springs from fear, the primal fear in humans stemming from the knowledge of death, which is as old as man. The second is communion with the actuality of death inseparable from life, which is the wellspring of life.
Having knowledge of death and not having an insight into thought (which is inherently separative), humans have separated death from life. I’ve even hard Buddhists say that death makes no sense to them. To my mind however, death gives meaning to life. Indeed, it’s the source of life.
It’s impossible to say what death is, besides that it is certain. One thing is certain about death however. It is the end of continuity. And that’s why we fear it.