Christmas or Christmas Day (Old English: Crīstesmæsse, meaning "Christ's Mass") is an annual festival commemorating the birthof Jesus Christ, observed most commonly on December 25  as a religious and cultural celebration among billions of people around the world.^] A feast central to the Christian liturgical year, it is prepared for by the season of Advent or the Nativity Fastand initiates the season of Christmastide, which historically in the West lasts twelve days and culminates on Twelfth Night;^[13] in some traditions, Christmastide includes an Octave.  Christmas Day is a public holiday in many of the world's nations, is celebrated culturally by a large number of non-Christian people, and is an integral part of the holiday season, while some Christian groups reject the celebration. In several countries, celebrating Christmas Eve on December 24 has the main focus rather than December 25, with gift-giving and sharing a traditional meal with the family.