æðr

Etymology
From, from ,.

Noun

 * 1) vein, vessel

Etymology 1
From, ; whence also 🇨🇬, , 🇨🇬 (🇨🇬).

Noun

 * 1) vein

Descendants
In Old Icelandic, the word lost its radical r, it being reinterpreted as a nominative ending, and comes to be nominative æðr, accusative and dative æði, genitive æðar, plural æðar, leading to the modern Icelandic, whereas the radical r is preserved in Faroese, as well as in the other Nordic languages.



Etymology 2
. Cognate to 🇨🇬, either from a common unattested language or through mutual loans. 🇨🇬 has been suggested, but it is inconsistent with either Sami cognates or the unattested masculine form *áðr, both suggesting a Proto-Germanic *aw(V)diz, probably. Derivations from an ultimate Proto-Indo-European are considered "unconvincing" by Guus Kroonen, which strengthens the non-Indo-European  hypothesis.

According to Watkins, from a root, from 🇨🇬, from a theoretical  root.

Compare the difficulty in precising the relationship between Old Norse and.

Noun

 * 1) eider