The earliest Germanic peoples worshipped Odin under the name Wotan or Woden, which gives rise to the English word “Wednesday.” His wife, Frigg, gives rise to the word “Friday.” The word “Thursday” comes from Thor. And “Tuesday” comes from Tiw or Tiwaz, another Germanic god of war.
Source: Wikimedia Commons. CC BY-SA 2.5.
It is worth noting that Tiw retains his presence in Scandinavian mythology under the name Tyr, but his role is essentially transferred to the figure of Odin.