Does Major Arcana Death mean literally death itself of querent or object of reading in readings? - The answer is No. This is the first thing that should be demystified. But as the name suggests, it certainly refers to some kind of the end. So, if there are more significators that point to physical death, it may suggest someone's death. But, honestly, from my experience, I can tell that Death very very rearly means physical death of a person. Actually, the personal death is more often represented by Minor Arcanas which at the first sight wouldn't be related to such big event as human death. It farther may mean that human death actually isn't such a big deal for the Universe and forces that are so much stronger than plain human life. Those forces are not only stronger, they are unreachable to small human life. There are forces which are known, unknown and unknowable. Human being, from his narrow perspective usually deals with the known, if it could be defineed as known and certain because of relativity of perception. Still, one has a chance to scratch under the surface of known and discern and perceive something from the area of unknown. The ironic fact is that the field of unknown is so wide that one single life isn't enough to scratch all layers of unknown. This is the field of The High Priestess and she has serious work at her hands deciphering Death.
Another reason why Major Arcana Death has almost nothing with physical death, unless it was supported by some Minor Arcanas, is following. Major Arcanas usually don't deal with physical plane in general, their field of influence is spiritual and higher mental realm. They represent everlasting present principles called archetypes. Archetypes are related with the plane of ideas and represent specific conceptual forms. Those forms find their expression trough certain patterns of humans behavior and state of mind. They are well-rounded contents of specific attributes which usual often roles are various temporal or durable identities. Observed from this perspective Major Arcana Death, similar as others Majors, tells us about spiritual and mental state of querant or person who is object of question. In case that the question is about event or situation Major Arcanas give us a hint about general ongoing trend. As they may represent temporal or durable attitude of person toward some matter, the same way they may represent the global picture of certain situation or event, or maybe most present force which effects the subject of question and at the same time this force is beyond the querant's influence and will.
As we go farther into this matter we can notice that not only that Major Arcanas (and Death among them) are not directly related to physical plane and realm of material world, they also represent forces which are beyond the human influence. We can call these influences destiny - that what was meant to be, or invisible and unconscious urges of our own psyche which push us to embrace certain identities. Identities come out from archetypes - those images and patterns which are deeply printed in psyche, and represent the certain roles which we all play. Some of those roles are temporal while some are more durable, some of them we chose intentionally or not and occasionally they are our response to certain circumstances. In summary, Major Arcanas have influence on physical and material but don't represent concrete physical and material manifestations. They represent ideas and notions, forces which lead and direct material manifestations. In that meaning, they are above in hierarchy and beyond the immediate reach of the eye and observing. There are few exceptions of this conclusion which often includes direct physical and material manifestation among those spiritual, mental, psychic or notional. Those exceptions are Major Arcanas The Devil, The World and sometimes The Empress. Those tree actually represent matter itself in various forms in accordance with meaning of each of those cards. Contrary to those tree, Death dissolve the matter. According to that, similar as The Judgment, Death releases from physical and material attachment to anything. As Death dissolve the matter, it could be said that Death effects any firm form and fixation in the same way - dissolving. In that meaning, Death shares certain similarities with The Tower. In Tarot journey, Major Arcanas Death and The Tower are the two Great Destroyers of any firm and tough form, no matter is that form conceptual, abstract or material. Difference between Death and The Tower is that Death tells us about cyclic processes and that life is a cycle with its ups and downs. Death certainly represents its downs which come regularly as inseparable part of cycle. In that way, those downs are predictable and the querant often gets prepared for them. While The Tower represents sudden changes, often unexpected which find querant unprepared.
The card Death is usually associated with the eighth zodiac sign Scorpio. Some authors relate card Death with planet Pluto and its astrological meaning. There are also some extraordinary interpretations of the authors who think outside the box. For example, card Death is named The Rebirth in One World Tarot deck where Crystal Love doesn't follow occult tradition and relates 13th Major Arcana with the sign Aries. Accordingly to title The Rebirth, relating thirteen Major Arcana with Aries zodiac sign makes a sense because it suggests new beginning, such a new life cycle. Another departure from usual correspondence makes A.E. Thierens, in General Book of the Tarot, and relate card Death with planet Saturn. Liz Hazel (The Whispering Tarot) links Death with Scorpio zodiac sign, also Pluto and sometimes Saturn. Associating houses with zodiac signs and their ruling planets is very well known system in modern astrology. So the first house is related to sign Aries and Aries'es ruling planet Mars. The second house is related to sign Taurus and its ruling planet Venus, and so on. So the eighth house is related to sign Scorpio and Scorpio's ruling planets Pluto and Mars. As the eighth house primary designates death, beside others, it comes as natural and logical to link card Death with eighth house, sign Scorpio and planet Pluto if we stick to modern astrology system. But, things are not always so plain, especially not in esoteric disciplines such Tarot and Astrology. On top of that, correspondences are not that simple even between Tarot and Astrology, so any tight attributions is misleading and falls off. Tight attributions also deprive us of deeper meanings and wider understandings.
There is a good reason for correspondence between tarot card Death and planet Saturn and eighth house. At the first place, Saturn in some way acts as the door on the way in and way out. By the birth, the doorway in, we get into form/shape, into body. The form give us certain limitations, the first of all limitation of time. The form, body, skeleton, limitations and time are all related to Saturn. Saturn, Hronos, the God of time eats his own children, he gives them a life and take it back. It also deals with karma and cycles of incarnations. Dying to be born again, and being born to die which is also cyclic process. As the door to way out, Saturn acts as Guardian of the gate in Solar system. Behind him are transcendent or outer planets Uranus, Neptune and Pluto. Transcending Saturn on spiritual level and releasing from his limitations makes influence of outer planets closer to our conscious mind. The similar may be told for the card Death.
In readings, at personal level, it mostly represents transition phase in process of great transformation. At the one side, what is behind, are old forms, old patterns of thoughts and behavior, worn out concepts, in few words an old ego-form. At the other side, in front, is something new, unknown and thus uncertain. This is an unexplored new field which needs to be discovered. You can guess, there is no study base and certainties which give any hope, support or security which could be counted on. It's such an empty space, there is no one, no help, no hold. There is no quick fixes and shortcuts nor revolutionary ideas or moves which may ease that state or make better fast. That state of emptiness and void is process which requires a certain time. There is nothing you can do against it unless to accept it. Trying to fight it may only delay that what is going to happen anyway, wanted or not. Death doesn't ask anyone for permission. Trying to runaway may only makes things worse, it will haunt you and happen anyway. This is an irrevocable process of self transformation when old believes are passing away. Many things that you claimed that you are, that is your character, what you believed is certain, appears to be unreliable, uncertain, vain and illusionary. Many masks and misconceptions will drop off. Finally there will remain only the core, the essence of your being, your true self. Accompanying feelings are feelings of emptiness, loneliness, dying inside, helplessness, numbness and everything else what opposes the idea of happy satisfying life. Slowly, fears are dying too. There could be only a fear because there is even no fears left, there is only empty space. That is a state when you wish you were truly dead, physically, so you can't think and observe yourself. But, you are not and won't be, at least not so easy. There is no shortcuts or easy ways. The bright side here is that this self disintegrating process is also cyclic, sooner or later the new self will be born and reintegrated again, based on new solid foundation. New self and form, ego built after this experience will be more in accordance to your true self and thus firmer and stronger. Similar goes for readings about any events and situations. Death announces changes that can't be avoided. They could be to worse or to better but they will necessarily happen. Very often card Death suggests that there is something that is rotten and transformation is of vital importance. No matter is that the false belief, worn out concept, wrong presupposition or assurance Death suggests that it won't work anymore like that. It needs to be changed or there will be loss. Also, if there are present big and idealistic expectations, Death forces us to face the truth as it is and to be realistic. It also may mean that event or situation effects the querent in the way of transformation which may be quite a challenge. It may lead the querent to review the whole thing and his believes about what she though it is and what actually is. What is beyond the surface and what is in the core of issue. Does it still have the meaning and importance to her as it had before or is it fading away. Does it block the querent and make him stagnant? If yes, the change is probably welcome and card Death announces that change. There could be a change that querent will not like but Death prepares her for upcoming changes and helps him to accept them. Usually, if Death appears upright, the querent is already ready for change, he may not be aware of that but deep inside he is ready. Death reverse suggest that someone is not ready to let go and is not prepared for new cycle so, intentionally or not, he tries to keep status quo. However, upright or reverse, Death means that transformation is needed, necessary and certain. No matter how much is delayed, it will happen anyway.
Some of alternative titles for Death card which can be found in various decks are: Transformation, The Rebirth, The Crossing... All of them make sense and hit the point. Obviously, listed alternative titles sound a way much lighter and optimistic than traditional title Death. No matter which term we choose it is still related to term death in one or the other meaning. If we choose Transformation it suggest that something or someone was an object of great change, passed through the phase of disintegration and destroying old form to reintegrate as new one (or be born again - rebirth). Obviously the old form doesn't exist anymore and it's dead. The form and matter is dying while energy is everlasting and lives through another form. If look at Rebirth, it implies that something had to die in one or another way to be reborn. The Crossing also refers to transition and changing form, passing from one to another, which again implies that something is left behind and new is starting.
Reading all from above you surely noticed that it is all about the death of old forms of matter. Matter doesn't exist without form, energy does. Matter is Energy compressed in form and shape. When form is fading, matter is dying and energy is released. Energy needs matter to express itself. Because of that, energy will always find a way to get into form and express itself through the matter. When the form gets to close and tight, worn out and doesn't serve it's primary purpose anymore, energy that made it turns to destroy and disintegrate it in order to made a new integrated once again. Card Death speaks that any form - matter or concept is meant to die if it doesn't serve the purpose anymore and the purpose is to transfer and transmit the energy. When form starts to block it, energy gets stuck and doesn't flow freely. Form tends to exist as separated and departed part, extending itself unchanged through the time and to become a purpose itself. Then Death takes it's part, to transform the form and release the energy to flow freely. It farther leads to conclusion that form should be adaptable and fluid, capable to modify itself to be able to persist in time, if not, it's going to be completely destroyed and become a history. Death is about cycles, irrevocable process, adaptability, accepting necessary changes, transformation, flow of energy and circulation of matter. About being subject of transformation who is able to actively transform oneself or being the object which passively endures it.
Form and matter are limited and represents limitation itself. Energy is unlimited. Form and matter are countable. Energy is uncountable. Form and matter are related to power because they are limited to such power by definition. Energy is related to might because it's uncountable. Form and matter need energy to get certain amount power which is volatile, to express themselves as part of living world. Energy needs the matter and form the express the might, to express her executive and effective state of functioning - to create and to destroy, to give a birth and devour her own children.