§ Terch Ungol ’the Spider’s Lair’ >> {Te} Torech Ungol ’the Spider’s Hole’ (WR:202)
These are Noldorin/Sindarin names for Shelob’s lair. Torech Ungol is mentioned in LotRIV, ch.9.
For ungol ’spider’ compare QL:12, root GUNU with Q. ungwe ’spider’, esp. Ungwe ’the Gloom-weaver’, Gn. gung ’spider’ (also GL:43). In The Etymologies UÑG- was reinterpreted as *’gloom’ with Q. ungwe ’gloom’, Ilk. ungol ’darkness, ungor ’black, dark, gloomy’, in N[oldorin] not used except in name Ungoliant. But LotR App.E already gives Q. ungwë ’spider’s web’ again. Thus one can suspect *uñg-la > *ungl > ungol ’spider’.
Terch ’lair’ may be related to TER-, TERES- ’pierce’, whence e.g. Q. tereva ’fine, acute’, teren ’slender’. The primitive form can be guessed as *ter’kā. One could imagine that the meaning ’pierce’ evolved into ’pierced passage, lair, tunnel’. Compare also Gn. tereg, terch ’a worm’ (GL:70), most probably related to TERE- with similar derivatives Q. tereva ’piercing, acute, shrill, sharp’, teren ’lissom, lithe’, teste ’small worm’ (QL:91). ’Worm’ seems to be derived here in a very similar way – a worm is not only slender, but also pierces its way through the ground.
Torech ’secret hole, lair’ comes from √TOR- ’secrete, hide’ and #ech < ekka ’hole’ (PE17:188)