two nights
Refers to a duration of two nights, often used in contexts like hotel stays or events spanning two nights.
I stayed at the hotel for two nights.
I stayed up all night for two nights in a row.
Compound of 二 (ふた, 'two') and 晩 (ばん, 'night'). The reading ふた is a native Japanese numeral for 'two', and ばん is the on'yomi of 晩.