§ Rhosfein >> Dant-ruin, Dant-ruinel (TI:273,283,285)
These are earlier names of the waterfall Rauros ’Rush-rain, Roar-rain’ (TI:285).
Rhosfein also appears as Rosfein (TI:315). It contains N. rhoss ’rain’, also occurring in the waterfall name Celebros ’Silver-rain’ (ROS2-), and fein ’white’ (SPAN-), thus meaning *’white rain’.
The other two forms contain dant ’fall’, cf. DAT-, DANT- ’fall down’, N. dant- ’to fall’ (later: MR:373).
The elements ruin and ruinel are more difficult in this context. Although Ruinnel ’Redway’ occurred earlier, there is no hint that this should be a *’red fall’, but without a translation this cannot be said with full confidence, of course. Judging by ’Rush-rain, Roar-rain’, ruin might be somehow related to N. †rhû ’sound of horns’ (Q. róma ’loud-sound, trumpet-sound’, ROM- ’loud noise’). Another possibility might be a derivation from RŌ- ’rise’, yielding words for ’east’, thus perhaps *rōnya > N. *r(h)uin ’eastern’? It might be also possible that ruin is just as later #rau- derived from RAW-, which yields words for ’lion’, but might have been an original onomatopoetic imitation of a roaring sound. In either case one would require an ending *-njā to arrive at the medial diphthong ui, compare N. rhaw ’lion’, pl. rhui < rōvi. Evidence for such an ending may be the formation of Q. menya ’our’ < *me-njā (VT43:19). Compare also echain (presumably from KAT-) below (2.67).
In ruinel we observe the suffix -el. It often appears in personal feminine names, but also in such noun formations as N. gandel, gannel ’a harp’ (ÑGAN-, ÑGÁNAD-), findel, finnel ’(braided) hair’ < sphíndele (SPIN-) or nelladel ’ringing of bells’ (NYEL-), perhaps also sarnel *’statue’ (see 3.8). This may confirm the assumption that ruin does not refer here to the colour ’red’ (as *’fall of redness’ would be most unusual). If the guess with the loud sound is right, the noun ’roaring’ might have been formed here.
Alternatively we could have in the last example #rui- *’loud, roaring’ (< *rōmjā?, compare also brui ’loud’ < Bruinen ’Loudwater’ (RC:171), G. rum, brum ’noise’ (GL:66)) + #nel, cognate of Q. nelle (< nen-le) ’brook’ (NEN-) as possibly in Ruinnel.
Ruin also occurs in Sarn Ruin, see directly below (2.40). Compare also Nen-uinel (2.59).