The Elvish words for “stone” were established very early as Q. ondo and S. gond. In the Qenya Lexicon of the 1910s Tolkien gave the root of these words as ᴱ√ONO “hard” with derivatives like ᴱQ. ondo “stone, rock” and ᴱQ. onin “anvil” (QL/70). But its Gnomish derivatives like G. gonn “stone” and G. gontha “pillar” (GL/41) indicate the actual root was ✱ᴱ√ƷONO, since initial ʒ > g in Gnomish.
In The Etymologies of the 1930s Tolkien gave the root as ᴹ√GONOD or √GONDO “stone” with essentially the same Elvish forms: ᴹQ. ondo and N. gonn (Ety/GOND). The root itself did not appear in later writings, but Tolkien continued to state, with great frequency, that the primitive form of the word was ✶gondō (Let/410; PE17/28; PE18/106; PE21/81; PM/374; RC/347).
The root ᴹ√BOR “endure” along with its extended form ᴹ√BORON appeared in The Etymologies of the 1930s along with various derivatives having to do with endurance, faithfulness and everlastingness (Ety/BOR, BORÓN). It was simply a later version of the root ᴱ√VORO from the Qenya Lexicon of the 1910s, unglossed but clearly of a similar meaning based on its Qenya and Gnomish derivatives like ᴱQ. voronda “faithful”, ᴱQ. vorima “everlasting” and G. bron(n) “steadfast, firm” (QL/102; GL/23-24).
Similar forms like Q. voronda or vórima “faithful” continued to appear in Tolkien’s later writing (UT/317). The well established names Q. Voronwë or S. Bronwe(g) “Steadfast, Faithful” retained the same basic form and meaning throughout Tolkien’s life, testifying to the enduring nature of the Elvish root for “endurance”.