Guða

As defined by the Cleasby & Vigfusson Old Norse to English dictionary:

guða

að, to shout ‘God;’ in Icel. it is the custom for a stranger arriving at a house at night after ‘day-set’ (dagsetr, q. v.), instead of knocking at the door, to climb to the louvre and shout, hér sé Guð, God be here! this is called að guða; the dialogue is well given in a ditty of Stefán Ólafsson, Hott, hott og hæ! Hér sé Guð í bæ! sælt fólkið allt! mér er sárkalt.—Svöruðu heima-hjú, Hvað heitir þú?—Eg heiti Jón, Jóhanns þjón, etc.; or in another ditty, Her sé Guð á góðum bæ | gestr er á ljóra | andsvörin eg engin fæ | ekki vaknar Þóra; or Guðað er nú á glugga | góðvinr kominn er, Jónas 119.

Possible runic inscription in Younger Futhark:ᚴᚢᚦᛅ
Younger Futhark runes were used from 8th to 12th centuries in Scandinavia and their overseas settlements