The permanent inanimation of the body
The body becomes still and the brain dies with it.
Without one the other cannot contain the human consciousness
Whatever you call it
The animation of the body ceceses upon death
The near death people experience is just that
Near
Not actual death
Any consciousness they remember having is likely a side effect of the brain resuming operations suddenly and needing to fill the gaps between when it was working and when it was not
True death is the final step into a world no one will ever tell the tales of
For true death is the abyss, the void, the event horizon of the blackhole
Where once you reach it only you see the otherside
To everyone else you just slowly fade away
Death is permanent and unavoidable make the countdown exciting if you can.