Os and Its Elder Futhark Cognate, Ansuz

Os is the fourth of the twenty four Futhorc runes carried from the Elder Futhark, where its cognate Ansuz names a god directly, generally read by runologists as Odin given the god's strong association elsewhere with eloquence, wisdom and oracular speech, qualities the Old English Os stanza preserves in its own reading of the mouth as a source of wisdom even after the specific divine name has been set aside. This makes Os one of the clearer cases where the underlying association, speech, wisdom, oracular or divine power channelled through the mouth, survives a change in the rune's literal referent, god becoming mouth, a pattern distinct from Thorn's shift, where troll became thorn plant with a shared sense of hazard rather than of eloquence carried across.

R. I. Page's survey treats the Os stanza as good evidence that whoever compiled the surviving Old English Rune Poem worked from inherited material whose pagan content required active, careful handling rather than wholesale invention, since a scribe starting from nothing would have had no particular reason to settle on mouth rather than any other available sense of the word os. Halsall's edition notes that a scribe working from inherited material had every reason to prefer a religiously neutral homophone over a name that still openly identified a pagan god, a small, careful choice rather than a careless one.