adverb, noun
all night; throughout the night
Describes an action or state that continues for the entire night. Often used with verbs like 働く, 話す, 遊ぶ, or 降る.
彼は夜通し働いた。
He worked all night.
雨が夜通し降り続いた。
The rain continued throughout the night.
一晩中 also means 'all night', but is more common in everyday speech. 夜通し is slightly more formal and often used in written or news contexts.
Compound of 夜 (yo, 'night') + 通し (tōshi, 'through, continuously'), from the verb 通す (tōsu, 'to let pass through').