noun, adverb
Refers to a single night or evening, often used when counting or specifying a duration.
一晩だけホテルに泊まった。
I stayed at a hotel for just one night.
一晩中、雨が降っていた。
It rained all night long.
noun, adverb
Emphasizes the entire night or something happening through the night; often used with 中 or in contexts of staying up or leaving something overnight.
一晩考えてから返事をします。
I'll give you my answer after thinking about it overnight.
彼は一晩中起きていた。
He stayed up all night.
一夜 also means 'one night' but often carries a more literary or dramatic nuance, and is common in set phrases like 一夜漬け (cramming overnight). 一晩 is more everyday and neutral.
夜通し means 'all night long' and is used adverbially, similar to 一晩中, but 一晩 can also simply mean 'one night' as a unit.
Compound of 一 (ひと, 'one') and 晩 (ばん, 'night, evening'). The reading ひとばん follows the native Japanese counting system.