Geit sú er Heiðrún heitir stendr uppi á Valhöll ok bítr barr af limum trés þess er mjök er nafnfrægt, er Léraðr heitir, en ór spenum hennar rennr mjöðr sá er hon fyllir skapker hvern dag. Þat er svá mikit at allir einherjar verða fulldruknir af. - [1]
A goat called Heiðrún stands up [on its hind-legs] in Valhalla biting the buds off the branches of that very famous tree which is called Lærað. From her teats runs the mead with which every day she fills a cauldron, which is so big that all the Einherjar can drink their fill from it. - Young's translation
Poetic Edda
In the Poetic Edda Heiðrún is mentioned twice. She is described in the Grímnismál in a way similar to Snorri's description.
Heiðrún heitir geit,
er stendr höllo á
ok bítr af læraðs limom;
skapker fylla
hón skal ins skíra miaðar,
knáat sú veig vanaz.
Heithrún, the goat
on the hall that stands,
eateth off Læráth's limbs;
the crocks she fills
with clearest mead,
will that drink not e'er be drained. - LMH's translation
Since Snorri quotes other strophes of Grímnismál it seems reasonable to assume that he knew this strophe too and used it as his source for his description of Heiðrún.
In the Hyndluljóð the giantess Hyndla (lit. bitch/she-dog) used the term "Heiðrún" to insult the goddess Freyja. Thorpe and some other translators translated the name straight to "she-goat".
The etymology of Heiðrún remains debatable.[2]Anatoly Liberman suggests that Heiðþyrnir, the name of the lowest heaven in Scandinavian mythology (from heið "bright sky"), was cut into two, and on the basis of those halves the names the heavenly goat Heiðrún and of the heavenly stag Eikþyrnir were formed (the element rún ~ run concealed several puns, but it is a common suffix of female names).[3] The etymology of the New High German name Heidrun is also debatable.
Heiðrún's name is sometimes anglicizedHeidrun, Heidhrun, Heithrun, Heidrún, Heithrún or Heidhrún.
Jón Helgason (Ed.). (1955). Eddadigte (3 vols.). Copenhagen: Munksgaard.
Liberman, Anatoly (2016). In Prayer and Laughter. Essays on Medieval Scandinavian and Germanic Mythology, Literature, and Culture. Paleograph Press. ISBN9785895260272.
Young, Jean I. (1964). Snorri Sturluson : the Prose Edda. Berkeley: University of California Press. ISBN0-520-01231-3.