n. [ Christ + mass. ] An annual church festival (December 25) and in some States a legal holiday, in memory of the birth of Christ, often celebrated by a particular church service, and also by special gifts, greetings, and hospitality. [ 1913 Webster ]

Christmas box. (a) A box in which presents are deposited at Christmas. (b) A present or small gratuity given to young people and servants at Christmas; a Christmas gift. --
Christmas carol, a carol sung at, or suitable for, Christmas. --
Christmas day. Same as Christmas. --
Christmas eve, the evening before Christmas. --
Christmas fern (Bot.), an evergreen North American fern (Aspidium acrostichoides), which is much used for decoration in winter. --
Christmas flower,
Christmas rose, the black hellebore, a poisonous plant of the buttercup family, which in Southern Europe often produces beautiful roselike flowers midwinter. --
Christmas tree, a small evergreen tree, set up indoors, to be decorated with bonbons, presents, etc., and illuminated on Christmas eve. [ 1913 Webster ]

n. 1. a spiny evergreen shrub of southeastern U. S. (Lycium carolinianum) having spreading branches with usually blue or mauve flowers and red berries.
Syn. -- Christmas berry, Lycium carolinianum. [ WordNet 1.5 ]

2. an ornamental evergreen treelike shrub of US Pacific coast (Photinia arbutifolia) having large white flowers and red berrylike fruits; often placed in genus Photinia.
Syn. -- toyon, tollon, Christmas berry, Heteromeles arbutifolia, Photinia arbutifolia. [ WordNet 1.5 ]

n. [ Christmas + tide time. ] The season of Christmas. [ 1913 Webster ]

n. The popular name for a poem by Clement Clarke Moore titled A Visit from St. Nicholas, a popular poem with the theme of St. Nicholas (Santa Claus) coming to bring gifts to children on Christmans eve. [ PJC ]

☞ The full text of the poem follows: T'was the night before Christmas, when all through the house,
Not a creature was stirring, not even a mouse;
The stockings were hung by the chimney with care,
In hopes that St. Nicholas soon would be there. The children were nestled all snug in their beds,
While visions of sugarplums danced in their heads;
And Mama in her kerchief and I in my cap,
Had just settled down for a long winter's nap. When out on the lawn there arose such a clatter,
I sprang from my bed to see what was the matter.
Away to the window I flew like a flash,
Tore open the shutters, and threw up the sash. The moon on the breast of the new-fallen snow,
Gave the luster of midday to objects below,
When what to my wondering eyes should appear,
But a miniature sleigh, and eight tiny reindeer.
With a little old driver, so lively and quick,
I knew in a moment it must be St. Nick. More rapid than eagles his coursers they came,
And he whistled, and shouted, and called them by name:
“Now, Dasher! Now, Dancer!, Now Prancer and Vixen!
On, Comet! On, Cupid!, On, Donner and Blitzen!
To the top of the porch! To the top of the wall!
Now dash away! Dash away! Dash away all!!” As the dry leaves that before the wild hurricane fly,
When they meet with an obstacle, mount to the sky,
So up to the housetop the coursers they flew,
With a sleigh full of toys, and St. Nicholas, too. And then in a twinkling, I heard on the roof,
The prancing and pawing of each little hoof.
As I drew in my head, and was turning around,
Down the chimney St. Nicholas came with a bound. He was dressed all in fur, from his head to his foot,
And his clothes were all tarnished with ashes and soot.
A bundle of toys he had flung on his back,
And he looked like a peddler just opening his pack. His eyes -- how they twinkled! His dimples, how merry!
His cheeks were like roses, his nose like a cherry!
His droll little mouth was drawn up like a bow,
And the beard on his chin was as white as the snow;
He had a broad face and a little round belly,
That shook when he laughed, like a bowl full of jelly.
He was chubby and plump, a right jolly old elf,
And I laughed when I saw him, in spite of myself.
A wink of his eye, and a twist of his head,
Soon gave me to know I had nothing to dread. He spoke not a word, but went staight to his work,
And filled all the stockings, then turned with a jerk,
And laying a finger aside of his nose,
And giving a nod, up the chimney he rose; He sprang to his sleigh, to his team gave a whistle,
And away they all flew like the down of a thistle.
But I heard him exclaim as he drove out of sight,
“Merry Christmas to all, and to all a good night!” [ PJC ]