Wednesday
The Greek and Roman God "Hermis" or "Mercury" respectively giving his namesake to the planet Mercury was the basis for the name Wednesday. The English version however was derived from the corresponding Norse God 'Wodan" (Odin) and the day being referred to as 'Woden's day". The mythological God Hermis, Mercurii, or Odin was the god of wisdom, travel, commerce, and even theft. It is also believed that Santa Claus was derived from the Viking God Odin.
Fun Fact: Although different countries consider Wednesday either the 3rd or 4th day of the week, it is often called the "hump day", or the middle of the week.