noun
spanning the New Year; continuing into the new year
Describes events, broadcasts, or activities that start before New Year's and continue past midnight into the new year. The term itself is rare, but the concept is common in contexts like TV specials or year-end parties.
年またぎの特番が放送された。
A special program spanning the New Year was broadcast.
年またぎのイベントに参加した。
I participated in an event that continued into the new year.
年越し is the common word for seeing the old year out and welcoming the new one, focusing on the moment of transition. 年またぎ emphasizes the continuous span across the year boundary.
Compound of 年 (year) and 跨ぎ (straddling, from 跨ぐ 'to step over'). The kanji spelling 年跨 is a direct representation, while 年またぎ uses kana for the second part.