Christmas or Christmas Day is a holiday generally observed on December 25 to commemorate the birth of Jesus, the central figure of Christianity. The date is not known to be the actual birthday of Jesus, and may have initially been chosen to correspond with either the day exactly nine months after Christians believe Jesus to have been conceived, the date of the Roman winter solstice, or one of various ancient winter festivals. Christmas is central to the Christmas and holiday season, and in Christianity marks the beginning of the larger season of Christmastide, which lasts twelve days.
Although nominally a Christian holiday, Christmas is also celebrated by an increasing number of non-Christians worldwide, and many of its popular celebratory customs have pre-Christian or secular themes and origins. Popular modern customs of the holiday include gift-giving, music, an exchange of Christmas cards, church celebrations, a special meal, and the display of various decorations; including Christmas trees, lights, garlands, mistletoe, nativity scenes, and holly. In addition, in Western Christianity several figures, known as Saint Nicholas, Father Christmas, and Santa Claus, among other names, are associated with bringing gifts to children during the Christmas season.
Because gift-giving and many other aspects of the Christmas festival involve heightened economic activity among both Christians and non-Christians, the holiday has become a significant event and a key sales period for retailers and businesses. The economic impact of Christmas is a factor that has grown steadily over the past few centuries in many regions of the world.
The word Christmas originated as a compound meaning "Christ's Mass". It is derived from the Middle English Christemasse and Old English Cristes mæsse, a phrase first recorded in 1038. "Cristes" is from Greek Christos and "mæsse" is from Latin missa (the holy mass).
Christmas Day is celebrated as a major festival and public holiday in countries around the world, including many whose populations are mostly non-Christian. In some non-Christian countries, periods of former colonial rule introduced the celebration (e.g. Hong Kong); in others, Christian minorities or foreign cultural influences have led populations to observe the holiday. Countries such as Japan and Korea, where Christmas is popular despite there being only a small number of Christians, have adopted many of the secular aspects of Christmas, such as gift-giving, decorations and Christmas trees. Notable countries in which Christmas is not a formal public holiday include People's Republic of China, (excepting Hong Kong and Macao), Japan, Saudi Arabia, Algeria, Thailand, Nepal, Iran, Turkey and North Korea. Christmas celebrations around the world can vary markedly in form, reflecting differing cultural and national traditions.
Among countries with a strong Christian tradition, a variety of Christmas celebrations have developed that incorporate regional and local cultures. For Christians, participating in a religious service plays an important part in the recognition of the season. Christmas, along with Easter, is the period of highest annual church attendance. In Catholic countries, the people hold religious processions or parades in the days preceding Christmas. In other countries, secular processions or parades featuring Santa Claus and other seasonal figures are often held. Family reunions and the exchange of gifts are a widespread feature of the season. Gift giving takes place on Christmas Day in most countries. Others practice gift giving on December 6, Saint Nicholas Day, and January 6, Epiphany.
For centuries, Christian writers accepted that Christmas was the actual date on which Jesus was born. In the early 18th century, scholars began proposing alternative explanations. Isaac Newton argued that the date of Christmas was selected to correspond with the winter solstice, which the Romans called bruma and celebrated on December 25. In 1743, German Protestant Paul Ernst Jablonski argued Christmas was placed on December 25 to correspond with the Roman solar holiday Dies Natalis Solis Invicti and was therefore a "paganization" that debased the true church. In 1889, Louis Duchesne suggested that the date of Christmas was calculated as nine months after Annunciation, the traditional date of the conception of Jesus.
The December 25 date may have been selected by the church in Rome in the early 4th century. At this time, a church calendar was created and other holidays were also placed on solar dates: "It is cosmic symbolism...which inspired the Church leadership in Rome to elect the winter solstice, December 25, as the birthday of Christ, and the summer solstice as that of John the Baptist, supplemented by the equinoxes as their respective dates of conception. While they were aware that pagans called this day the 'birthday' of Sol Invictus, this did not concern them and it did not play any role in their choice of date for Christmas," according to modern scholar S.E. Hijmans.
However, today, whether or not the birth date of Jesus is on December 25 is not considered to be an important issue in mainstream Christian denominations; rather, celebrating the coming of God into the world in the form of man to atone for the sins of humanity is considered to be the primary meaning of Christmas.