It's interesting how Jesus redefines the meaning of words. It means that when you first read something He says, you might "read into" its meaning based on the meaning of words that you already have, and therefore not understand what He's saying.
Jesus clearly says that the entire dream of separation is a dream of death.
Jesus clearly says that even a slight amount of unhappiness or grievance is a state of death.
Jesus clearly says that all forms of sickness are "a little death."
Jesus clearly says that the separation idea was an attempt to oppose God's will and to be totally opposite to His creation. His creation is life, so this is an idea of death.
Jesus says death is the central dream from which all illusions stem, AND that the last illusion to be overcome - really the ENTIRE illusion, is death.
Jesus clearly says that all things which seem like "life forms" in this world only have an appearance of life at best, and death at worst.
Jesus clearly says that there is no life outside of heaven, so anything outside of heaven is technically "death".
Jesus also clearly says that without the idea of death, there is no world.
It goes on and on. So what must be happening here is, Jesus is using the word "death" to refer to things that ACTUALLY ARE death, in that they are opposite to or opposed to what is ACTUALLY life. But WE did not previously understand these things to BE death.
So it's like, we do not RECOGNIZE what death IS, or the various states and forms that death takes. We haven't recognized that even a slight grievance is an idea of murder ("what is not love is murder".). We haven't recognized that sickness is death, or that the world is death, or that without death there is no planet Earth, or that this world is entirely MADE OF the idea of death, without which there is no world here at all.
So Jesus doesn't so much use meanings and terms with the definition we're familiar with. Nor does he necessarily use dictionary definitions. He basically teaches us WHAT HIS definition is, and his definition is in line with what is ACTUALLY TRUE, rather than what we've THOUGHT was true. e.g. Death is not just "what happens when a body dies."
So that means we have to UN-LEARN what we've taught ourselves and open ourselves up to learning what Jesus is teaching us is the "correct recognition" of what something is. If we don't do that, and we maintain EGO definitions for things, such as that death is only a body in the ground, and that a pre-death state of sickness and suffering "has no death in it", then we are now mistaken and deceived by appearances.
Jesus does the same thing with various other terms as well, because what He's trying to teach us is the TRUTH rather than our strange twisted and distorted interpretations. We have a big problem with not RECOGNIZING the truth, OR recognizing illusions, OR recognizing this world for what it is. We don't even recognize that we're dreaming and that everything we see here is an illusion.
So we have to go through a process of learning and redefining and letting go and opening up and allowing ourselves to receive a new outlook on life, a new way of regarding what's going on here, and learn to see it all from Holy Spirit's perspective. And that's going to have to entail realizing that we've been mistaken, illusions we thought were real are not real, and the truth about this world is not what we thought it was.