Is there a term for immortality that only prevents death from old age? For example, the elves from The Lord of the Rings are "immortal", but only to the effects of dying from age. They can still be killed from wounds. So they are technically not immortal. In fact, the use of the term "immortal" permeates many facets of Science Fiction & Fantasy lore in a similar context (Justice League and Dungeons & Dragons come to mind).

Is there a more fitting term for this kind of longevity, perhaps used by other Sci-Fi/Fantasy works of which I am not aware? Specifically, I am looking for a term either from actual science or Sci-Fi/Fantasy that dictates the state of growing to maturity, and then no longer suffering from aging or be capable of dying to the effects of aging while still maintaining vulnerability to wounds.

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    Although this looks like it may be a better fit on English Language/English Learners (which one has single word requests?), immortality is very much a SF thing and we have such "terms" questions. As per the "unclear" part, it appears LOTR is only given as an example, although a Tolkien-word for it might be a nice addition to an answer. TLDR: voted to leave open.
    – Jenayah
    Commented Feb 15, 2019 at 21:42
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    To quote Wikipedia, Immortal beings and species abound in fiction, especially fantasy fiction, and the meaning of "immortal" tends to vary.
    – gowenfawr
    Commented Feb 15, 2019 at 21:52
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    @Valorum truth be told, I (myself, not speaking for anyone else nor judging) wouldn't take any enjoyment in answering in such a way, but I still do think this is somewhat on-topic for the site, although not the "best question evah"
    – Jenayah
    Commented Feb 15, 2019 at 22:50
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    @Jenayah - The question "What word in LOTR describes the Elves immortality" would be fine on the site. The question "Is there a word in the English language that describes non-aging" would also be fine, but not here.
    – Valorum
    Commented Feb 15, 2019 at 23:05
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    Usually that's precisely what "immortality" means. Not being killable by wounds would be "invincibility". "I'm immortal, not invincible". I would have made this an answer if the question wasn't protected.
    – Kapten-N
    Commented Feb 18, 2019 at 13:09

10 Answers 10


Negligible senescence largely fits the bill.

Negligible senescence is a term coined by biogerontologist Caleb Finch to denote organisms that do not exhibit evidence of senescence (biological aging), such as measurable reductions in their reproductive capability, measurable functional decline, or rising death rates with age.

Biological immortality is the more extreme version.

Biological immortality (sometimes referred to bio-indefinite mortality) is a state in which the rate of mortality from senescence is stable or decreasing, thus decoupling it from chronological age. Various unicellular and multicellular species, including some vertebrates, achieve this state either throughout their existence or after living long enough. A biologically immortal living being can still die from means other than senescence, such as through injury or disease.

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    Came here to post this. +1 for science facts! Commented Feb 16, 2019 at 8:05
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    This seems to be the most correct answer: a term which means exactly what the OP is looking for (not something vague/ambiguous like "ageless" or "eternal") and which isn't restricted to a single work or subgenre of SFF.
    – Rand al'Thor
    Commented Feb 16, 2019 at 10:59
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    "The Postmortal" by Drew Magary postulated a formula that would, when taken, basically freeze you at your current age. You could, however, still be killed by violence or even disease. Commented Feb 16, 2019 at 22:45
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    Because we all watched the movies about Connor MacLeod the negligibly senescencent, and we read about Elrond the biologically immortal, and the ancient Greeks were all warm and fuzzy for Zeus, the negligibly senescencent god of Olympus...
    – motoDrizzt
    Commented Feb 19, 2019 at 9:32
  • @motoDrizzt: I see your point. And my answer may be on the side of "providing a scientific explanation". :)
    – FuzzyBoots
    Commented Feb 20, 2019 at 17:37

"ageless" would work as it means: something (or someone) that does not look or appear to grow older

Elrond's face is described as ageless (lotr, many meetings)

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    "Ageless" typically describes appearance and can still apply to beings that do age. I don't think that's a good fit.
    – isanae
    Commented Feb 16, 2019 at 4:23
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    -1 for being a poor answer to the question. "Ageless" doesn't (usually) literally mean someone who can't age. Someone's face may appear ageless (they're not showing the effects of their age), but that's not a sci-fi/fantasy concept. Immortality is.
    – Rand al'Thor
    Commented Feb 16, 2019 at 9:15
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    @Randal'Thor - While being ageless (or more commonly the lesser reference of "appearing ageless") can be used in non- scifi/fantasy contexts, when used in a scifi/fantasy context it does tend to mean what Garret Gang describes - that one exists without (dramatic) aging, without dying of natural causes, but one is still able to be killed by violence, etc. And it is usually pretty clear in a given story which context the term is used in, scifi/fantasy or not. This was actually the answer I came up with when I read the question.
    – Megha
    Commented Feb 17, 2019 at 3:28
  • Ageless is an adjective. The question was asking about a term for immortality/longevity, indicating a noun. Even before I read this answer, the first word that popped into my head was "agelessness".
    – TOOGAM
    Commented Feb 18, 2019 at 0:07
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    Whoie I agree with Rand AL Thor that ageless when used to describe someone outside of science fiction/fantasy merely means they do not look old. I feel that inside of the realm of science fi/fantasy the term generally refers to a race, or person who does not age. And I feel this use of the term was inspired by Tolkien work, though upon rereading the chapter, I think he used it to mean that elronds face was neither young nor old, giving no indication to his actual age.
    – Pliny
    Commented Feb 24, 2019 at 0:09

Undying is a term that refers specifically to a state of never being in a process of dying (such as Tolkien's Undying Lands), and applies mainly to life, rather than ideas, art, or appearance. It does not necessarily mean being immune to being killed or destroyed, but rather to not being subject to life's usual condition of growing progressively closer to death.

It also does not necessarily mean being immune to some form of change due to aging (for the better or for the worse); it does, however, mean being immune to death from aging.

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    Note: Undying may be confused with, or used interchangeably with, undead, which typically refers to reanimated dead (e.g. zombies).
    – NotThatGuy
    Commented Feb 16, 2019 at 12:41
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    @NotThatGuy Maybe, although I doubt it. Could perhaps be true for very young readers. But I have never seen "undying" used that way or confused with "undead." Additionally, "undead" is such a well-established term that a deviation from it would be more likely to emphasize that you don't mean "undead."
    – Misha R
    Commented Feb 16, 2019 at 17:44

Turning to roleplaying games, GURPS uses "Unkillable" for "immune to death by violence" and "Unaging" for "never growing older once mature".

  • I always ponder over what those "immune to death by violence" would do at the end of the universe if they cannot die?
    – miroxlav
    Commented Feb 19, 2019 at 8:21
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    In GURPS? If there was no envionment left that could support their life they would still exist but in a state of perpetual unconsciousness unless some new universe came along to provide a livable condition for them. Unless of course they also had metabolic immunity and didn't need a habitable environment. Commented Feb 19, 2019 at 9:16
  • – so then they are merely spirits, putting on material bodies only when possible, i.e. when an universe is temporarily available.
    – miroxlav
    Commented Feb 19, 2019 at 9:22

Eternal youth. From Wikipedia:

Eternal youth is the concept of human physical immortality free of ageing. The youth referred to is usually meant to be in contrast to the depredations of aging, rather than a specific age of the human lifespan. Achieving eternal youth so far remains beyond the capabilities of scientific technology. However, much research is being conducted in the sciences of genetics which may allow manipulation of the aging process in the future.[citation needed] Eternal youth is common in mythology, and is a popular theme in fiction.

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    "Eternal youth" implies that the subject, well, stays young. It wouldn't be used to describe someone who keeps on getting older and older, but never dies of it.
    – user41830
    Commented Feb 16, 2019 at 6:45
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    "Eternal youth" in the context of fiction is generally used to describe people invincible to death by old age. See the Wikipedia article I linked. Unless you're trying to include some possibility of "you can still physically age, but you won't die from it," eternal youthfulness is how I would describe the example given in the OP, i.e. the elves from LOTR. Commented Feb 16, 2019 at 8:02
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    @duskwuff I'd argue that the common scifi/fantasy trope usually refers to effects that essentially stop aging at the adult stage, having the equivalent of a prime-age human body for millenia. The term should reflect "that the subject, well, stays young" as opposed to someone who keeps visibly aging, becoming equivalent to a 80 year old human with the accumulated bodily changes of aging, then to a 100 year old human with even more such changes, and getting older and older but never dying from it. That would be possible in some story, but that's not the common scenario we're talking about.
    – Peteris
    Commented Feb 17, 2019 at 2:14
  • @duskwuff : The question explicitly stated "growing to maturity, and then no longer suffering from aging", so this answer is valid. It also shows that the OP was not meaning a struldbrugg-like immortality.
    – vsz
    Commented Feb 20, 2019 at 5:36

The term “immorbidity” is used in some SF, for example Wil McCarthy’s Queendom of Sol series.

  • I learned something today! That's very useful. ... ok, not very useful, but it could be if magic was real. Or at some point in the future when I'm dead but technology can achieve effective immorbidity.
    – einpoklum
    Commented Feb 18, 2019 at 0:13

While this question already has an answer, I'd like to add my two-cents.

From any dictionary definition I've looked at, Immortality means :

The ability to live forever; eternal life.

This definitions fits your criteria :

no longer suffering from aging or be capable of dying to the effects of aging while still maintaining vulnerability to wounds

Since in the definition of Immortality, no mention is made as to any resistance to wounds, illness, or anything else.

Someone who is unable to die from wounds is not immortal, but Invulnerable :

incapable of being wounded, hurt, or damaged.

So while it's true that immortality is commonly used to talk about someone/something that cannot die, or be killed, by definition it only refer to someone/something who cannot die from old age.

  • As one gets older, the probability of meeting a fatal accident increases asymptotically towards 1. "The ability to live forever" is therefore predicated on being able to survive what would otherwise be fatal accidents.
    – Sneftel
    Commented Feb 19, 2019 at 10:14
  • @Sneftel the probability of meeting a fatal accident as one gets older, in and of itself is predicated around the idea of "aging", but anyone being able to live forever would most likely stop to age. Otherwise their body would inevitably stop functionning at some point.
    – user3399
    Commented Feb 19, 2019 at 16:38
  • No, it's nothing to do with aging. As your lifespan increases, the likelihood of a low-probability event occuring (like a fatal accident) increases.
    – Sneftel
    Commented Feb 19, 2019 at 16:53
  • @Sneftel Okay, but even then, the definition of Immortality itself only says "The ability to live forever; eternal life". It does not imply that you cannot be involved into an accident, that you cannot be killed or anything else. It litterally only says that someone Immortal has "The ability to live forever", it does not mean that they will.
    – user3399
    Commented Feb 19, 2019 at 16:59
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    @GarretGang This is due to the way the word has been used, in litterature someone/something that is immortal is often something that cannot die, nor be killed, unless specific means are used. Wich led to the word Immortal to be interpreted a bit differently than its textbook definition.
    – user3399
    Commented Feb 25, 2019 at 7:49

In sci-fi, this is often called "functionally immortal."

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    Some instances would be nice :) (you can edit them into your answer)
    – Jenayah
    Commented Feb 16, 2019 at 4:28
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    Yes, please include some examples or references for this term. Answers are best when properly sourced or supported. Thanks :-)
    – Rand al'Thor
    Commented Feb 16, 2019 at 7:07

Tolkien used the words immortality and immortals to describe the elves. He also used the term longevity, modified in various ways at various times.

It should be noted that Tolkien's elves are not just resistant to old age. They do not suffer disease, and can heal from injuries that would be fatal to a Man. Even if an elf is "killed" by the total destruction of the body, the elf's "spirit" remai8ns in the world, and may in proper cases be re-embodied or re-born as a child but with full memory of his or her previous life. (Tolkien's views on re-birth vs re-embodiment changed over his life.) Glorfindel seems to be an example: he was killed during the sack of Gondolin, but was alive and in the flesh during The Fellowship of the Ring several thousand years later.

The issue is discussed in detail in "Laws and Customs of the Eldar" starting on pager 207 of Morgoth's Ring and again later in the "Dialog of Arabeth and Finrod" later in that volume.

Elves have as their proper lifespan the life of the world itself, and it seems that exactly two elves in all of history have "died indeed and left the world" Luthien and Arwen.

I don't know of an SF or fantasy race that has a llifespan quite like that of Tolkien's elves.


Possible terms for the kind of immortality brought about by halting aging include 'agelessness' 'indefinitely extended life', and 'biological immortality'.

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    When answering a question like this, you should examples of where such terms have been used (preferably examples that haven't already been given by other users). Commented Mar 16 at 9:40
  • Two of these three have already been suggested. The other is just a dictionary definition and not helpful.
    – Valorum
    Commented Mar 16 at 10:35

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