watchnight

noun4

1. •
   A religious service involving a review of the past year and preparation for the year ahead participated in by Methodists and members of other Christian denominations which usually starts late on New Year's Eve and ends after midnight on New Year's Day; hence, the night that begins on December 31 and ends on January 1.

   • The first watch night services ever held in Grace Protestant Episcopal Church were but poorly attended, […] — 1901
2. •
   Any religious or spiritual vigil.
3. •
   (historical) A monthly or quarterly religious service participated in by Methodists which extended past midnight.
4. •
   A night watchman.