Staying up all night; to pass the night awake—either by choice (all-nighter) or to keep vigil/watch overnight.
試験前は夜明かしして勉強する学生も多いが、体調管理に注意が必要だ。
Many students pull all-nighters before exams, but they should watch their health.
赤ちゃんが生まれたばかりで、親は毎日夜明かしが続いている。
With the newborn baby, the parents have been staying up all night every day.
停電で家族と一緒にキャンドルを灯して夜明かしした。
During the power outage we stayed up together with candles and passed the night.