Definitions of Christmas:

• noun:   a Christian holiday celebrating the birth of Christ; a quarter day in England, Wales, and Ireland
• noun:   period extending from Dec. 24 to Jan. 6
• verb:   spend Christmas

  Example: "We were christmassing in New York"

• name:  A surname (rare: 1 in 33333 families; popularity rank in the U.S.: #4757)