New Year's Eve
US /ˌnuː jɪrz ˈiːv/
UK /ˌnuː jɪrz ˈiːv/

1.
大晦日
the last day of the year, December 31, which is celebrated with parties and other festivities leading up to midnight and the start of the new year
:
•
We're planning a big party for New Year's Eve.
大晦日に盛大なパーティーを計画しています。
•
Many people watch fireworks on New Year's Eve.
多くの人が大晦日に花火を見ます。