Depending on the body granted to him, the materialistic being wanders from one planet to another, absorbed in self-interested action, the fruits of which he endlessly reaps.
Depending on his self-interested actions, the conditioned being obtains an appropriate body, with a material mind and senses. Then, the consequences of these actions end; this is called death. When a new set of karmic reactions begins, then comes birth.
When the eyes lose their ability to perceive colors or shapes due to some morbid condition of the optic nerve, vision dies, and the living being, the one who governs both the eye and sight, loses his visual power. Similarly, when the physical body, the place where sensory perceptions arise, becomes incapable of perceiving anything, what is called death occurs. And the moment when one begins to regard the body as one's own self is called birth. Therefore, no one should view death with horror, nor be tempted to define the body as the soul, nor excessively enjoy the necessities of life. Realizing one's true nature, the distinct being must evolve in this world, without attachment and remaining fixed on one's goal.
Equipped with right vision and strengthened by devotional service as well as a pessimistic attitude toward the material ego, one must, through reason, relegate one's body to the illusory world. Thus, one can lose all interest in the material world.
In the end, what is death?
Death is, above all, being separated from God, being distant from Him, and no longer knowing anything about Him. It is falling into forgetfulness of God, no longer knowing anything about Him, to the point of believing that He does not exist. Death is the exchange of one's material body for a new one, the old one becoming unusable for various reasons.
Death is the forgetting that we are in reality a spiritual soul, and not the material body with which we wrongly identify. It is the ignorance of our true spiritual identity.
Death is the complete ignorance of existential truth.
Death, or being plunged into death, is the telling of lies* with the aim of misleading people, and thus plunging them into forgetfulness of God and the truth, into the darkness of ignorance, perdition, suffering, and perpetual confinement in matter.
Death is synonymous with forgetfulness.