Thor was the Norse God of Thunder. The Scandanavians believed his chariot rumbled as it crossed the sky and that he wielded a hammer that shot lightening when he threw it. The Angles and Saxons who invaded England in the 500's carried the belief in Thor with them in their wanderings and wars.
In the days before the invasion, the Romans inhabited most of the civilized world (including most of England). The fifth day of the week was known as "dies jovis". The Romans had named it for their own God of Thunder, and also chief of the Gods, Jupiter.
When the Germanic tribes suplanted the resident Romans of England they also suplanted their Gods. They replaced Jupiter or Jove with Thor. Thus came the name, Thorsdaeg which comes down to modern English speakers as Thursday.
There are two holidays that traditionally fall on Thursday. One is Maundy Thursday. It is the Thursday upon the eve of Good Friday. Biblical accounts have it that the "Last Supper" was on a Thursday, and it was at this meal that Christ gave the "mandate" to his disciples to "love one another". The word Maundy is a corruption of the Latin word "mandate".
One of the most popular holidays in the United States is Thanksgiving. It always falls on the fourth Thursday in November. Although it has been celebrated continuously since 1623, it was not made an official holiday until 1863 when President Abraham Lincoln recommended the feast day to Congress. More than a celebration of bountiful harvests, it was a direct response to two Union victories during the American Civil War, Gettysburg and Vicksburg.
Wednesday | Friday