1. The Church festival on the 25th of December, in memory of the birth of Christ; Christmas day.

2. Belonging to the period of Christmas or its festivities. See Mass.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• chridtmas,
• chistmass,
• chistmas,
• christman,
• chrisymas,
• chritsmas,
• christnas,
• chritmas,
• chtristmas,
• chritmass,
• christms,
• chiristmas,
• christmad,
• christam,
• crhistmas,
• chrismas,
• chriastmas,
• chrictmas,
• christmass,
• chrinstmas

• Christy,
• Christinia,
• christenson,
• christendom,
• Christon,
• christ,
• Christo,
• christianson,
• Christiani,
• christening,
• christly,
• christlike,
• Christoper,
• christian,
• Christensen,
• cristal,
• christiansen,
• christiania,
• Christa,
• Christiane,
• Christology,
• charcot,
• Christine,
• Christal,
• Christel,
• Christi,
• Chrystal,
• Christain,
• Cristina,
• Crista,
• chrest,
• christless,
• christison,
• Christena,
• Christeen,
• Christia,
• cherrystone,
• Christianise,
• CHRISTMAN,
• chrostowski,
• chorister,
• christoff,
• christeson,
• Christians,
• charest,
• Christin,
• christopher,
• Christley,
• Christ Plant,
• Christion,
• christen,
• christella,
• christianly,
• Christiano,
• christner,
• Christiana,
• Christene,
• Christina,
• christie,
• cherished.

The adverb form of "Christmas" is "Christmassy".

The adjective form of "Christmas" is "Christmas".

The plural form of the word "Christmas" is "Christmases"

The singular form of the word "Christmas" is still "Christmas".