'New Year's' definitions:
Definition of 'New Year's'
From: WordNet
noun
The first day of the year [syn: New Year's Day, New Year's, January 1]
Definition of 'New year's'
From: GCIDE
- New Year's Day \New" Year's` Day"\ the first day of a calendar year; the first day of January. Often colloquially abbreviated to New year's or new year. [1913 Webster]