§ Thilevril (TI:184)
This was an earlier name of the substance Mithril, changed from Erceleb and Ithil (see 1.20).
In The Etymologies we find Silevril (RIL-) as the Noldorin cogante of Q. Silmaril. Thilevril is obviously formed with the parallel stem THIL- instead of SIL-. Literally it would mean *’silvery brilliance’.