ᴹ√TULUK root. “*support, prop; steady, firm”
An unglossed root in The Etymologies of the 1930s with derivatives like ᴹQ. tulka “firm, strong, immoveable, steadfast”, N. tolog “stalwart, trusty”, and ᴹQ. tulko/N. tulu “support, prop” (Ety/TULUK). The “steady, firm” senses of the 1930s root are consistent with derivatives of the earlier root ᴱ√TULUK from the Qenya Lexicon of the 1910s with derivatives like ᴱQ. tulka- “fix, stick in, set up, establish”, G. tulga- “make firm, confirm, settle, steady; comfort” and ᴱQ. tulunka/G. tulug “steady, firm” (QL/95; GL/71); nearby ᴱ√TḶKḶ (with no derivatives) may also have been related (QL/93).
However, the Qenya Lexicon of the 1910s had a distinct root ᴱ√TḶPḶ with derivatives like ᴱQ. talpa/G. talp “support, prop”, ᴱQ. tulpu-/G. talpa- “prop up”, and G. clib- “uphold, support” (QL/93; GL/26, 69). This ᴱ√TḶPḶ may have been related to ᴱ√TULU as presented in the Qenya Lexicon, which in this document had the more ancient sense “uphold, support” (QL/95). Thus I think the 1930s derivatives of ᴹ√TULUK having to do with “support” may have been transferred from 1910s ᴱ√TḶPḶ.
Reference ✧ Ety/TULUK
ᴱ√TḶPḶ root. “*support, prop”
References ✧ GL/26, 69; QL/93
ᴱ√TULUKU root. “*steady, firm”
References ✧ LT1A/Tulkas; QL/95