A root Tolkien introduced in the late 1960s as the basis for his latest Elvish word for “ten”: Q. quëan/quain, S. pae, T. pai(n) (VT42/24; VT48/6). It was an extension of √KWA “complete” as in “a complete set of (10) fingers”. Prior this late change, the usual word for “ten” was ᴹQ. kainen (along with other variants beginning with kai- or kea-) from the root ᴹ√KAYAN or ᴹ√KAYAR as it appeared in The Etymologies of the 1930s (Ety/KAYAN). This basis for “ten” dates back to the Early Qenya Grammar of the 1920s (PE14/49, PE14/82). Tolkien was still considering √KAYAN for “10” in the late 1960s before replacing it with √KWAY(AM) (VT48/12).
Primitive elvish
lay
root. *be alive, flourish, [ᴱ√] be alive, flourish
ezdē
noun. rest
kayan
root. ten
kway
root. ten
sed
root. rest
This root first appeared as ᴹ√SED “rest” in The Etymologies of the 1930s with derivatives like ᴹQ. sére “rest, repose, peace” and N. sîdh “peace”, along with the name of the Valië ᴹQ. Este < ᴹ✶ezdē (Ety/SED). The root √SED “rest” along with the etymology of Este reappeared in both the Outline of Phonetic Development (OP1) from the 1940s (PE19/45) and the Outline of Phonology (OP2) from the early 1950s (PE19/92), and again in revisions to the OP2 page annotated in green ink and thus probably from 1970 (PE19/91 and note #110).
The root √SED “rest” was mentioned a couple times in the Quenya Verbal System (QVS) from 1948 as the basis for the verb ᴹQ. ser- “rest, repose” (PE22/102, 125) and again (unglossed) in the Quendi and Eldar essay of 1959-60 as the basis for Este (WJ/403). In the sense “peace” this root had some competition, however. In the first version of the Gloria in Excelsis Deo prayer from the mid-1960s, Tolkien used Q. sívë for “peace”, revised to Q. sérë in the second version and then Q. rainë (VT44/32). The word Q. sívë “peace” reappeared in unpublished etymological notes from 1969 derived from the root √SIB “rest, quiet” (VT44/35).
Neo-Eldarin: For purposes of Neo-Eldarin, I would use √SED for the act of resting and so Q. sérë “peace” = “restfulness (personal peace)”, and would use √SIB = “quiet, ✱stillness, absence of activity” and so Q. sívë “peace” = “absence of activity or violence (environmental peace)”. I would use Q. rainë as “good will” in connection to √RAY “smile”.
This root was primarily used as the basis for Elvish words for summer and, via its extended root √LAYAK, freshness and greenness. Its earliest appearance was as ᴱ√LAẎA “be alive, flourish” in the Qenya Lexicon of the 1910s (QL/52) where the Ẏ indicated an ancient palatal spirant, [c] or [ɟ]. In this period it had derivatives like ᴱQ. laiqa/G. laib “green” and ᴱQ. laire/G. glair “meadow” (QL/52; GL/39, 52).
In The Etymologies of the 1930s ᴹ√LAYA was unglossed with a single derivative ᴹQ. laire “summer”, appearing in a marginal note next to more detailed ᴹ√LAYAK (EtyAC/LAYA). In this document, Tolkien gave the derivatives of ᴹ√LAYAK as ᴹQ. laiqa “green” vs. N. lhoeb “fresh” (Ety/LAYAK). The Ilkorin form laig “fresh, lively; keen, sharp” was said to be blended with ᴹ√LAIK “keen, sharp, acute” (Ety/LAIK), so “✱fresh” was probably the original meaning of ᴹ√LAYAK.
The root √LAY appeared quite regularly in Tolkien’s later writings, but was never glossed. It was mentioned in the second version of Tengwesta Qenderinwa from around 1950 as an example of a bi-consonantal root (PE18/97). It appeared in 1957 etymological notes as the basis for “summer” and “green”: the former still Q. lairë but the latter now Q. laika (PE17/145, 159). It was mentioned again in a 1958 letter to Rhona Beare as the basis for “summer” and ”green”, with the Sindarin form S. laeg having largely been replaced by S. calen “green” (Let/282).
Most likely this root retained the same basic sense as it had in the Qenya Lexicon, connected as it was to words having to do with freshness and liveliness.