"On the slab runes were deeply graven:"

Runes
Public DomainRunes - Credit: wikimedia commons
Tolkien’s dwarvish runic script is called Cirth.

The word rune comes from ‘runa’, a Proto-Norse word meaning ‘secret’ or ‘whisper.’ Runes are letters used in runic alphabets of Germanic languages, before the Latin alphabet was introduced in the early Middle Ages. The term runes might also be applied to some other unrelated historical alphabets.