In the Gregorian calendar, New Year's Eve, also known as Old Year's Day or Saint Sylvester's Day in many countries.
In the Gregorian calendar, New Year's Eve, also known as New Year's Day or Saint Sylvester's Day in many countries, is the evening or full day of the last day of the year, on December 31. The last day of the year is commonly referred to as "New Year's Eve". In many countries, New Year's Eve is celebrated