Erilaz or Erilaʀ is a Migration period Proto-Norse word attested on various Elder Futhark inscriptions, which has often been interpreted to mean "magician" or "rune master",[1] i.e., one who is capable of writing runes to magical effect. However, as Mees (2003) has shown, the word is an ablaut variant of earl, and is also thought to be linguistically related to the name of the tribe of the Heruli, so it is probably merely an old Germanic military title (see etymology below).