The earliest iteration of this root was unglossed ᴱ√FANA or ᴱ√FṆTṆ (the latter marked with a “?”) in the Qenya Lexicon of the 1910s with derivatives like ᴱQ. fanóre “day-dream”, ᴱQ. fansa “swoon”, and ᴱQ. fantl “vision, dream, hazy notion, imaginary idea” (QL/37). The root ᴹ√PHAN also appeared in The Etymologies of the 1930s, but the entry was unglossed, empty and eventually deleted (EtyAC/PHAN), perhaps supplanted by ᴹ√SPAN; see that entry for discussion.
√PHAN appeared quite a few times in Tolkien’s later writings, however, mostly in connection to Q. fanya “cloud” from the Namárië poem and S. Fanuilos as a name for Elbereth in the Sindarin prayer A Elbereth Gilthoniel. In connection to Fanuilos Tolkien said: “√FAN ‘white’, but especially applied to reflected light as of clouds, snow, frost, mist. Cf. fanya, Quenya, (white) cloud” (PE17/26). In a more extensive note he wrote:
> The element FAN- (Q fana, S fân) is “elvish” and not easy to translate. It may be said to mean “shape”, but with the added notion of light and whiteness; it is thus often used where we might use “a vision” — of something beautiful or sublime. Yet being elvish, though it may be used of things remote, it has no implication either of uncertainty or unreality. The Fân here is the vision of the majesty of Elbereth upon the mountain where she dwelt. So that Fanuilos really means in full: Figure (bright and majestic) upon Uilos (PE17/26).
Tolkien also wrote a lengthy essay discussing this root in several versions (PE17/173-180). The second version of this essay began:
> √PHAN-. The basic sense of this was “cover, screen, veil”, but it had a special development in the Eldarin tongues. This was largely due to what appears to have been its very ancient application to clouds, especially to separate floating clouds as (partial) veils over the blue sky, or over the sun, moon, or stars. This application of the most primitive derivative ✱phanā (Q fana, S fân) was so ancient that when ✱phanā (or other derivatives) was applied to lesser, handmade, things this was felt to be a transference from the sense “cloud”, and words of this group were mainly applied to things of soft textures, veils, mantles, curtains and the like, of white or pale colours (PE17/174).
Finally, in The Road Goes Ever On (RGEO) from 1967, Tolkien wrote:
> Fana- is an Elvish element, with primary meaning “veil”. The S. form fân, fan- was usually applied to clouds, floating as veils over the blue sky or the sun or moon or resting on hills. In Quenya, however, the simple word fana acquired a special sense. Owing to the close association of the High-Elves with the Valar, it was applied to the “veils” or “raiment” in which the Valar presented themselves to physical eyes ... The High-Elves said these forms were always to some degree radiant, as if suffused from a light within. In Quenya, fana thus came to signify the radiant and majestic figure of one of the great Valar. In Sindarin, especially as used by the High-Elves, the originally identical word fân “cloud” was also given the same sense (RGEO/66).
This discussion in RGEO is essentially a summary of the much lengthier essay on √PHAN noted above. Thus it seems Tolkien’s latest notion of the root was that it originally mean “cover, screen, veil”, and was applied to clouds as veiling the sun, and from this application the root came to refer to white, radiant and soft things. In the Quenya of Valinor the word Q. fana was then applied to the radiant materialized bodies of the Valar, and when the Noldor again encountered the Sindar this sense influenced S. fân (originally just “cloud”) as well.
Tolkien used similar roots for “dream” and “sleep” throughout his life, but the exact details varied. In the Qenya Lexicon of the 1910s he gave the root ᴱ√OLO as the basis for the names ᴱQ. Eriol “a dreamer” and ᴱQ. Olofantor who had to do with sleep (QL/69). It had an extended form ᴱ√OLOR with derivatives like ᴱQ. olóre “dream”, but Tolkien indicated these form more properly belonged to the root ᴱ√LORO (QL/69). The entry for ᴱ√LORO had glosses “doze, slumber”, along with derivatives like ᴱQ. lor- “slumber”, ᴱQ. lorda “slumbrous, drowsy”, and ᴱQ. Lôrien “King of Dreams” (QL/56). Various derivatives also appeared in the contemporaneous Gnomish Lexicon such as G. lor- “sleep deep, dream (tr.)”, G. lorc “drowsy, dreamy, lazy”, and G. lûr “slumber” (GL/54, 55), along with G. olma- “dream” and G. oloth “dream, apparition, vision”, probably from ᴱ√OLO³ (GL/62).
In The Etymologies of the 1930s Tolkien first gave the root ᴹ√LOS, revised it to ᴹ√LOR, and then back to ᴹ√LOS (EtyAC/LOS). Tolkien also gave an augmented variant ᴹ√OLOR, which was likewise altered to ᴹ√OLOS (EtyAC/ÓLOS). The unaugmented root was glossed “sleep”, and the augmented root “dream”. The unaugmented root had derivatives like ᴹQ. lóre “slumber” and ᴹQ. lorna “sleep” (Ety/LOS), with Noldorin cognates N. lhûr “slumber” and N. lhorn “asleep” rejected after ᴹ√LOR >> ᴹ√LOS (EtyAC/LOS). The augmented root had derivatives ᴹQ. olor “dream”, N. ôl “dream”, and N. oltha- “to dream” (Ety/ÓLOS). The Quenya form ᴹQ. olor may reflect Tolkien indecision in this period on the development of final -s: compare ᴹQ. kár (kas-) “head” (Ety/KAS). Ultimately he would decide that final -s survived, and intervocalic -s- > -r-, making the derivation of ᴹQ. olor from ᴹ√OLOS somewhat dubious.
In both the 1910s and 1930s, lor- forms were more closely associated with “sleep” and ol- forms with “dreams”. In writings from the 1950s and 60s, the only attested associations for these roots were with “dreams” and “visions”. Tolkien gave √OLOR “vision (of mind)” (PE17/88), olo-s “vision, fantasy” (UT/396) and √OLOS/R “dream” (PM/341). This last mention of the root was from The Shibboleth of Fëanor from the late 1960s, which indicated the root was an extension √OL, but Tolkien continued to use Q. lórë for “dream” in this period (PE17/80; Let/308), and the unaugmented root √LOR was mentioned in passing (without gloss) in a discussion of the root √DOR (PE17/181).
In later writings, Tolkien also used √OLOR or √OLOS as the basis for the true name of Gandalf: Q. Olórin (PE17/88; UT/396). In connection to that name Tolkien wrote:
> olo-s: vision, “phantasy”: Common Elvish name for “construction of the mind” not actually (pre)existing in Eä apart from the construction, but by the Eldar capable of being by Art (Karmë) made visible and sensible. Olos is usually applied to fair constructions having solely an artistic object, i.e. not having the object of deception, or of acquiring power (UT/396).
And also:
> Olor is a word often translated “dream”, but that does not refer to (most) human “dreams”, certainly not the dreams of sleep. To the Eldar it included the vivid contents of their memory, as of their imagination: it referred in fact to clear vision, in the mind, of things not physically present at the body’s situation. But not only to an idea, but to a full clothing of this in particular form and detail (UT/396).
Thus in Tolkien’s later conception, perhaps the most accurate translation of the root would be “(mental) vision”, not properly connected to “sleep” or “(sleeping) dreams” at all. However, the translation of the root as “vision of the mind” seems to have been intertwined with Galdalf’s Quenya name, and remnants of early ideas continued to appear, most especially the long-lived name Q. Lórien “✱Dream Lands” (S/28) as well as S. Lothlórien “Dream Flower” (LotR/467).
Neo-Eldarin: For purposes of Neo-Eldarin, using this root only for “vision of the mind” is problematic, in that it leaves us no good words for “sleep” or “(ordinary) dream”, nor any good explanation for the name (Loth)lórien. I think it is better to hearken back to earlier notions, and assume two distinct roots that influenced each other: √LOR “sleep” and √OLOS “dream, vision”. In Sindarin their derivatives would remain distinct, but in Quenya the two produce similar results, so that Q. lórë came to meaning “dreaming sleep”, usable for either dreams or sleep or both, where Q. olos properly meant “vision of the mind”, but sometimes took the form olor under the influence of √LOR.