Friday is the fourth and last day of the week to be named after a Germanic or Norse deity. In this case, the etymological culprit is the goddess Frigg (alternatively spelled Frigga, Frija, and Frea in Germanic variants or Frige in Old English), the wife of Odin (see the etymology of Wednesday) and a generally wise omniscient being. She also rides around in a chariot pulled by cats. That covered, Friday in Old English was spelled frigedæg, and obviously meant "Frigg's day". This, also pretty obviously, is a portmanteau of Frige (the previously discussed Old English spelling of Frigg) and dæg, meaning "day". Frige, Frigg, and all relatives alike travel back to the Proto-Germanic word frijjo, which still described the goddess but as a weird hybrid with the Roman goddess Venus, just as Odin was fused with Mercury and Thor with Odin. For the third time, it's weird. After a few conjugations, we can make our way back to frijaz, meaning "free", and ultimately reconstruct it to Proto-Indo-European prihos, meaning "beloved".
Adam Aleksic, a rising sophomore studying linguistics and government at Harvard University, has been described as the internet's sixth most famous etymologist. He also has disturbing interests in politics, vexillology, geography, board games, conlanging, and law.