§ Neleg Thilim >> Neleglos ’the White Tooth’ (WR:106)
This is an older name of Minas Ithil (internally). An analysis is given in Lambengolmor message #921 by Philipp Marquart .
Both forms transparently contain N. neleg ’tooth’ (NÉL-EK-). The adjective thilim looks like being derived from THIL-, a root parallel to SIL- ’shine silver’. So one can isolate the adjectival ending -im, which already occurred in #mithim *’hoar, grey’, Nenvithim ’Hoardales’ (TI:114) – see above (2.1).
Neleglos likely contains N. gloss ’snow, also adj. snow-white’ (GOLÓS-); later we find S. gloss ’(dazzling) white’ from (G)LOS- (VT42:18).