Die is defined as ceasing to live, exist, or disappear. An example of this is pulling a plant out of the ground by its roots. An example of death is when a person's heart stops and the brain stops working. stop living; dead out.
Use ``die of'' when someone dies of direct causes. We use ``die of'' when someone died from an indirect cause. "die by" is used when someone dies from something. He died of cancer.
