Frigg

Frigg (lit. "free") is an ásynja of Norse mythology, belonging to the Æsir. She is heavily associated with foresight and wisdom, and dwells with Fensalir. She is the wife of Oðinn. She is the representation of the earth itself, and has at times been referred to as Jörð (lit. "Earth"). Due to similarities, scholars have proposed that Frigg and Freyja are one in the same. The word Friday derives from fredag ("Frigg's Day"). She is mentioned several times in the Eddas, primarily in relation to Oðinn.

Sources:

"Days of the week Meanings. The origins of the names of the seven days of the week". education.newarchaeology.com.
Grundy, Stephan (1998). "Freyja and Frigg". In Billington, Sandra; Green, Miranda (eds.). The Concept of the Goddess. Routledge. ISBN 0-415-19789-9.
Faulkes, Anthony (Trans.) (1995). Edda. Everyman. ISBN 0-460-87616-3.
Hollander, Lee Milton (Trans.) (2007). Heimskringla: History of the Kings of Norway. University of Texas Press. ISBN 978-0-292-73061-8.
Larrington, Carolyne (Trans.) (1999). The Poetic Edda. Oxford World's Classics. ISBN 0-19-283946-2.
Simek, Rudolf (2007). Dictionary of Northern Mythology. translated by Angela Hall. D.S. Brewer. ISBN 978-0-85991-513-7.
horpe, Benjamin (Trans.) (1907). Edda Sæmundar Hinns Frôða: The Edda of Sæmund the Learned Part I. London: Trübner & Co.