Hello. This question isn't so much for writing purposes, but out of general interest. Is there a specific and technical name for the concept of a legendary land or mythological place? The only one I can think of that applies is the 'Otherworld', but that's perhaps too specific to Celtic mythology. That name also suggests a kind of secondary world, but that's not always the case with these domains. This is by my far my favourite concept and it brings me joy to think about fantastical or otherworldly regions or sites imbued with power and mystery. I'd just like to be able to place it better so that I can find more books and other resources on it. I need an overarching name or term that fits anything from Lemuria to Middle Earth to Paradise. Any help is appreciated. Thanks.
Anthropologists applied the name "Dreamtime" or "the Dreaming" to Australian aboriginal concepts of the mythic/sacred realm, though there is dispute as to the accuracy of this label. Discussions of shamanistic practice often discuss Upper and Lower Worlds, sometimes connected by a sacred tree or mountain. Faerie, Fairyland, or Elfland can refer to a mythic realm in some Western folklore. Often mythic realms are situated in specific places on earth, such as mountains, islands, lakes, eg Kunlun and Penglai in Daoist folklore. Buddhism has an extremely elaborate cosmology with all kinds of different realms, most famous being the Pure Lands created by various Buddhas.
I think it solely depends on the culture. I know in Hungarian culture there's three "names" often associated: "Fairy-tale land" / Meseföld, "Elfland" / Tündérország or a more interesting term "Túl az Óperenciás Tengeren" which means "Beyond the Óperenc sea" which is in turn a Hungarization of the term "Ob der Enns" referring to lands beyond the Enns river in Austria, a Napoleonic-era term used by the French soldiers to campaigns outside the German theater. Interestingly, the soldiers used the term to refer to lands east of the Enns river, whereas Hungarians tended to imagine these lands to the west. From the Germanic side, you've got all the Viking world names at your disposal - each in turn is a "description" of the land itself. These are interesting because several distant lands to the German cultural sphere also have "mythic" names attached to them; places that Germanic people reached but still regarded as "exotic" and "legendary". Two of the most known are Holmgard (Isle City) referring to Novgorod and Miklagard (Big City) referring to Constantinoples. The Hellenic "Underworld" is also worthwhile to mention. Following on the Hungarian description above, it's also interesting to find the Greek underworld defined by five rivers. Tartarus is one specific part of the underworld, not the whole underworld itself which has no specific name other than the occasional reference as "Hades" which is also the patron god presiding over it. Must also note the mythical lands of the Greek that they presumed to lie beyond their scope of the world; Atlantis beyond the Pillars of Heracles (Giblaltar) or Dyonisus' cave which was originally placed similarly to the far west, then Alexander the Great realized the Himalayas match the description so declared it to be there.
To piggy-back on this excellent answer, you need to develop the culture you are writing about and invent their own interpretation of the otherworld you speak of. How does it play into their history and what beliefs they have attributed to it will help you determine the name of the otherworld. You can use other culture's versions, but those are subjects to the limitations of that said culture. If you invent your own, you're free to design it in line with the culture of the people you are also developing.
Thanks for the responses. I did indeed think of the word Faerie as I'm especially familiar with this, but I didn't include it as I take it to mean a still quite specific body of English or Gaelic folklore. Although I suppose that Faerie can also be meant as another realm. However, what I actually meant by my OP was that I'm looking for an almost scientific, overarching conceptual word that describes everything included in your answers and more, if possible. That is, something outside of culture but also attached to all cultures. Perhaps something like a word a comparative mythologist might use. Something that encapsulates all imaginary or "escapist" realms.
I run into terms like "mythic geography," "realm of myth," etc. Related is Mircea Eliade's concept of "Sacred Time".
The Astral Plane? https://en.wikipedia.org/wiki/Astral_plane These might help you come up with a term (research purposes): Esotericism: https://simple.wikipedia.org/wiki/Esotericism Hermeticism: https://simple.wikipedia.org/wiki/Hermeticism