§ Elements in Quenya and Sindarin Names The Silmarillion

kheliek- 'ice' in Helcar, Helcaraxë (Quenya helka 'icy, ice-cold'). But in Helevorn the first element is Sindarin heledh 'glass', taken from Khuzdul kheled (cf. Kheled-zaram 'Mirrormere'); Helevorn means 'black glass' (cf. galvorn).