Definition of mithril in US English:

mithril

noun

  • In the fiction of J. R. R. Tolkien (subsequently adopted in other fantasy contexts with reference to Tolkien): a rare silver-coloured precious metal of great hardness and beauty.

Origin

1940s; earliest use found in J. R. R. Tolkien (1892–1973), writer and philologist. An arbitrary formation, explained by J. R. R. Tolkien in relation to other words in his invented Elvish language.

Pronunciation

mithril

/ˈmɪθrɪl/