√KIM root. “edge, brink of”
Tolkien used the root √KIM and similar roots for a wide variety of purposes throughout his life. Perhaps the earliest of these was the Early Qenya word ᴱQ. kim- “heed” from the Qenya Lexicon of the 1910s, but all of its Gnomish cognates begin with g-, as in G. gima- “hear” and G. gimri “hearkening, attention” (GL/38), so this early root was most likely *ᴱ√GIMI. In the Quenya Verbal System of the 1940s, Tolkien had ᴹ√KIM “light on, find, come by” and along with a verb ᴹQ. kim- of similar meaning (PE22/103, 108, 125) but most likely this meaning of the root was transferred to √KHIR and Q. hir- “find” (PE17/75).
Finally in notes from 1969 Tolkien gave √KIM “edge, brink of”, replacing deleted forms √KIL and √KILIM, with the root √KIL being reassigned the meaning “choose, select” (which seems to be the normal meaning of √KIL throughout the 1950s and 60s). Note that the early root ᴱ√KILI the Qenya Lexicon of the 1910s also meant “edge”, but somewhat interestly there is a Gnomish word G. cim “blade”, perhaps indicating that this vacillation between √KIM vs. √KIL for “edge” had a longer history in Tolkien’s conceptual development of the languages.
Neo-Eldarin: For purposes of Neo-Eldarin, I would recommend using √KIM = “edge” and √KIL = “choose”.
References ✧ PE22/149
ᴹ√KIM root. “light on, find, come by”
References ✧ PE22/103, 125
*ᴱ√GIMI root. “*heed, pay attention”