Christmas or Christmas Day (Old English: Crīstesmæsse, literally "Christ's mass") is an annual commemoration of the birth of Jesus Christ,^[5][6] celebrated generally on December 25^[2][3][4] as a religious and cultural holiday by billions of people around the world. A feast central to the Christian liturgical year, it closes the Advent season and initiates the twelve days of Christmastide.^[7] Christmas is a civil holiday in many of the world's nations,^[8][9][10] is celebrated by an increasing number of non-Christians,^[1][11][12] and is an integral part of the Christmas and holiday season.

The precise year of Jesus' birth, which some historians place between 7 and 2 BC, is unknown.^[13][14] By the early-to-mid 4th century, Western Christianity had placed Christmas on December 25, a date later adopted in the East.^[15][16] The date of Christmas may have initially been chosen to correspond with the day exactly nine months after the Annunciation, the date Christians believe Jesus to have been conceived,^[17] as well as the date of the southern solstice, i.e., the Roman winter solstice), with a sun connection being possible because Christians consider Jesus to be the "Sun of righteousness" prophesied in Malachi 4:2.^{[17][18][19][20][21]}