Christmas or Christmas Day is a holiday observed(遵守或奉行（宗教或習(xí)俗）） generally on December 25 to commemorate [k??mem?reit]（紀(jì)念）the birth of Jesus, the central figure of Christianity（基督教）. 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 some early Christians believed Jesus had been conceived（認(rèn)為，當(dāng)作）,the date of the Roman winter solstice [?s?lstis]（冬至）,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（圣誕節(jié)期間，圣誕節(jié)節(jié)期）, which lasts twelve days.

       Although nominally [?n?m?n?l?]（從名義上）a Christian holiday, Christmas is also celebrated by an increasing amount of non-Christians worldwide,and many of its popular celebratory customs have pre-Christian （基督以前的）or secular（非宗教性的） themes and origins. Popular modern customs of the holiday include gift-giving, music, an exchange of greeting cards, church celebrations, a special meal, and the display of various decorations（裝飾品，裝飾物）; including Christmas trees, lights, garlands（花環(huán)）, mistletoe（槲寄生，其小枝常用作圣誕節(jié)的裝飾）, nativity [n??t?v?ti:, ne?-]（耶穌誕生）scenes, and holly. In addition, several similar mythological figures, known as Saint Nicholas（圣誕老人）, Father Christmas（圣誕老人） and Santa Claus（圣誕老人） 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 （零售商）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.