Isa

The Futhark was a germanic alphabet: It's runes had names and were associated with gods or other mythological things.

The rune "Isa" (or Is) belongs to "Heimdall's Aett". Isa was assossiated with ice, isolation, frost giants, silence and conschiousness.

Meaning: Ice
Gods/Deities: Frost Giants, Ymir and Verdandi
Letter Value: I