Tuesday is the day of the week between Monday and Wednesday. According to international standard ISO 8601, Monday is the first day of the week; thus, Tuesday is the second day of the week.[1] According to many traditional calendars, however, Sunday is the first day of the week, so Tuesday is the third day of the week. In some Muslim countries, Saturday is the first day of the week and thus Tuesday is the fourth day of the week.
The English name is derived from Middle English Tewesday, from Old English Tiwesdæg meaning "Tīw's Day", the day of Tiw or Týr, the god of single combat, law, and justice in Norse mythology. Tiw was equated with Mars in the interpretatio germanica, and the name of the day is a translation of Latin dies Martis.