I’m not an expert in naming this, but I will share my point of view:
The mental body is the mind, in the context of mind/body/spirit complex.
The energy body is the spirit, in the context of mind/body/spirit complex.
The astral body is the projection of the energy body/spirit in the 3rd Density sphere as the unmaterial being. Of course it is also possible to enter higher Densities, theoretically it may even result in separation from the body and death. I don’t know, I don’t practice astral travel.
Trance, depending on the depth of trance, can be about getting into the spirit, bypassing the blockages and intrusions of the mind, up to turning it off, turning off consciousness in the sense of everyday consciousness, while the spirit still remains in the body.
Dreaming is contact with spirit that is captured and sometimes even remembered by the mind. Spirit may be your higher selves coming from one of the higher Densities, or the energy and consciousness of other entities.
Meditation is focusing inward on yourself. Our higher parts of ourselves are within. The higher worlds are also within us. When we die, we also collapse in on ourselves. We don’t go anywhere, we go into ourselves, into our own consciousness.
Meditation is not separation from the body, it is contact with spirit, with the difference that the mind works differently than in the case of deep trance and turning off the conscious mind or sleeping/dreaming.
Meditation is a state between being awake, fully conscious as we are usually conscious, and the unconscious state, the state of sleep or deep trance.
Meditation is an internal search and work on the balance between the conscious mind and the deeper parts of ourselves. It’s like throwing a string and tying together everyday consciousness with resources of the spirit.