A noun in The Etymologies of the 1930s glossed “torrent, mountain-stream” derived from primitive ᴹ✶ulda (Ety/ULU), where the o became u via a-affection and the ld became ll as usual.
Noldorin
thórod
noun. torrent
thórod
noun. torrent
oll
noun. torrent, mountain-stream
rhib-
verb. to flow like a (?torrent)
A verb in The Etymologies of the 1930s glossed “to flow like a (?torrent)” [the last word is unclear] under the root ᴹ√RIP “rush, fly, fling” (Ety/RIP). It was related to the name N. Rhibdath or Rhimdath “Rushdown”. It had a past form rhimp followed by another form rhimmo, possibly a Noldorin-style infinitive of a longer variant ✱rhimma-.
Neo-Sindarin: Most Neo-Sindarin writers adapt this Noldorin word as ᴺS. rib- “arm” as suggested in HSD (HSD), since the unvoicing of initial r to rh was a feature of Noldorin of the 1930s but not Sindarin of the 1950s and 60s.
old
noun. torrent, mountain-stream
oll
noun. torrent, mountain-stream
rhib-
verb. to flow like a (torrent ?)
The reading of the gloss is uncertain
rhimma-
verb. to flow like a (?torrent)
siria-
verb. to flow
A noun for “torrent” in The Etymologies of the 1930s based on the root ᴹ√THOR “come swooping down” (Ety/THOR; EtyAC/THOR). In The Etymologies as published in The Lost Road Christopher Tolkien gave the form as thórod (LR/393), but Carl Hostetter and Patrick Wynne corrected this to thôrod in their Addenda and Corrigenda to the Etymologies (VT46/19). However, in normal Sindarin/Noldorin orthography ô is only used for monosyllables, so thórod is the expected form.