[1] Scholar Stephan Grundy comments that "the problem of whether Frigg or Freyja may have been a single goddess originally is a difficult one, made more so by the scantiness of pre-Viking Age references to Germanic goddesses, and the diverse quality of the sources.
"[2] The names Freyja and Vanir (the group of gods to which Freyja belongs) are not attested outside of Scandinavia, as opposed to the name of the goddess Frigg, who is mentioned as Frīg in Old English and as Frīja in Old High German, all stemming from Proto-Germanic *Frijjō.
[3] This theory, however, is rejected by most linguists in the field, who interpret the name Frigg as related to the Proto-Germanic verb *frijōn ('to love') and stemming from a substantivized feminine of the adjective *frijaz ('free'),[4][5] whereas Freyja is regarded as descending from a feminine form of *frawjōn ('lord').
[6][7] On the other hand, the names Freyja ('lady, mistress') and Freyr ('lord') are cognates stemming from the common root *frawjōn, which does not necessarily imply further relation.
[10] In the universe of Marvel Comics, Frigga the adopted mother of Thor and the Asgardian goddess Freya were initially written as different characters.