night; nighttime (the period of night; used for activities or conditions occurring during the night).
夜間は病院の入り口が閉まります。
The hospital entrance closes at night.
夜間の騒音で眠れないことがある。
Sometimes I can't sleep because of noise at night.
夜間は気温がぐっと下がる。
Temperatures drop sharply at night.