The first day of Christmas is December 25th, also known as Christmas Day. It is a holiday celebrated by Christians around the world to commemorate the birth of Jesus Christ. On this day, families and friends gather to exchange gifts, share meals, and spend time together. Many cultures have their own unique traditions and customs that they observe during the Christmas season, which can include decorating homes and trees, singing carols, and attending church services. Overall, the first day of Christmas is a time for reflection, gratitude, and celebration of the gift of love and hope that Jesus Christ brought to the world.