ᴹ√KHYEL(ES) root. “glass”
A root in The Etymologies of the 1930s glossed “glass” with derivatives in both Quenya and Noldorin with the same meaning: ᴹQ. hyelle and N. hele (Ety/KHYEL(ES)). After Tolkien changed Noldorin to Sindarin, he decided that “There was no common Eldarin word for glass”, and that the Sindarin word S. heledh was derived from Khuzdul kheled (PE17/37). Thus the root ᴹ√KHYEL(ES) was abandoned.
References ✧ Ety/KHYEL(ES); EtyAC/KHYEL(ES)