The symbols represent the runes Ansuz, Laguz, and Uruz. The origin and meaning of the word are matters of dispute, though a general agreement exists among scholars that the word represents an instance of historical runic magic or is a metaphor (or metonym) for it. It is the most common of the early runic charm words.
[…] Raetian North Etruscan dedicatory votive objects have been discovered featuring alu where the term means “dedication”. Connections have been proposed between these objects and the term alu found on runic inscriptions. Theories have been proposed that the term was loaned into Runic usage from this source.
Source: Alu (runic) – Wikipedia