noun
visiting a shrine on New Year's Eve and staying until New Year's Day
A traditional practice of visiting a shrine late on New Year's Eve and remaining there to welcome the new year, or returning home after midnight.
毎年、家族で二年参りに行きます。
Every year, our family goes to the shrine for the New Year's Eve visit and stays until New Year's Day.
Compound of 二年 (にねん, 'two years') and 参り (まいり, 'visiting a shrine'), referring to the act of visiting a shrine across two calendar years.