√KIL root. “choose, select”
This root has a long history in Tolkien’s writing, but it evolved in meaning over Tolkien’s life. The earliest form of this root was ᴱ√KILI “edge” from the Qenya Lexicon of the 1910s, with derivatives like ᴱQ. kíla/G. cilm “edge, rim” and ᴱQ. kilme/G. cail “lip” (QL/46, GL/24, 26). In The Etymologies of the 1930s it became ᴹ√KIL “divide” with derivatives ᴹQ. kilya/N. cîl “cleft, pass between hills, gorge” (Ety/KIL). This sense seems to have been abandoned when Tolkien changed ᴹQ. Kalakilya “Pass of Light” (LR/173) to Q. Calacirya (LotR/377).
In etymological notes from 1969 Tolkien gave √KIL “choose, select” vs. √KIM “edge, brink of”, along with various derivatives of √KIL having to do with choices (PE22/149). One of these, Q. cilmë, appeared as an element in words from several essays on Elvish names from the 1950s and 60s: Q. Essecilmë “[Ceremony of] Name-choosing” (MR/214; PE21/84) and Q. kilmessi “self-names, names of personal choice” (PM/339). But it seems even in the 1969 note mentioned above that Tolkien was considering the earlier senses of the root, since he first gave √KIL/√KILIM as the basis for edge words (PE22/149 note #26).
The difference in sense is not that great between 1910s ᴱ√KILI “edge” >> 1930s ᴹ√KIL “separate” >> 1960s √KIL “choose”, so Tolkien’s conceptual shifts on the meaning of this root seem to be gradual, with him still considering the earlier meanings into the late 1960s.
Reference ✧ PE22/149 ✧ “choose, select”
ᴹ√KIL root. “divide”
References ✧ Ety/KIL, THOR
ᴱ√KILI root. “edge”
Reference ✧ QL/46 ✧ “edge”