The Collaborative International Dictionary of English v.0.48:
Saint Nicholas \Saint Nicholas\, St Nicholas \St. Nicholas\, n.
A Dutch saint, who was reputed to bring gifts to children on
Christmas even, giving rise to the modern legend of Santa
A Visit from St. Nicholas The original name for a poem by
Clement Clarke Moore, popularly called titled The Night
Before Christmans. It is a popular poem with the theme of
St. Nicholas (Santa Claus) coming to bring gifts to
children on Christmans eve. See Night Before Christmas
in the vocabulary.