The Gregorian calendar's final day, celebrated immediately before New Year's Day, is called New Year's Eve.
New Year's Eve falls on December 31 in the Gregorian calendar. It is the evening and, in common usage, the entire final day before January 1. Celebrations often include parties, public concerts, religious services, fireworks, countdowns, and family meals.
The date is not the world's only New Year's Eve. Calendars that use different systems or religious observances can mark the new year at other times, including Lunar New Year and Rosh Hashanah. Even so, December 31 is the internationally familiar year-end date in countries using the Gregorian calendar for civil purposes.
The word “eve” traditionally means the day or evening before a significant festival or holiday. Thus, New Year's Eve is parallel in form to Christmas Eve, but it is not the same occasion. New Year's Day begins on January 1, immediately after the midnight transition from December 31.