The Old Norse word galdr belongs to the semantic field of singing and calling. Literary sources describe formulae, protective chants, and knowledge made effective through voice and verse.
No melodies or complete performance instructions survive. Metre, repetition, and naming may have mattered, but modern sonic reconstructions remain speculative.
Runes and galdr appear together in some texts but are not identical. A carved inscription, a rune name, and a sung charm must be distinguished through source criticism.