You may have a defective starter motor, or a flat battery, or a serious hydraulic problem stopping a piston passing top dead centre. Take out the spark plugs and or glow plugs then turn over the engine on the starter, if successful you have an internal engine problem
You can tell if it is dead when it stops moving and turns black.
Your blood stops flowing. Without oxygen the blood turns blue, causing the dead to look pale. The blood will be drained out when embalmed for burial.
when your heart stops
Dead
They are dead when their heart stops beating and breathing. Generally their body stops working either from old age, illness or injury.
No Holden Is Not Dead
A deadball in basketball is when someone who is dribbling the ball, stops dribbling. That person is just stuck in that spot until a teammate comes to retrieve the ball. You can only be "dead" for 5 seconds with a defender on you.
If your battery is in the trunk, have the mechanic check the connection between the battery & the engine.
That means its dead
When all brain activity stops.
Dead
Because it's not yet "dead". An engine is designed to turn at a minimum amount of RPMs under that level the engine is not balanced and shakes. For the brief period after you shut off the engine the cylinder chambers are not getting the optimal amount of fuel for proper combustion until they get no fuel and the engine stops.