English

Adjective

nightlong ‎(not comparable)

1. Lasting a night (i.e. the duration of one night); lasting all night.

Etymology 2

From Middle English nihtlonge, nihtlonges, from Old English nihtlanges ‎(“for the night”), equivalent to night +‎ long.

Adverb

nightlong ‎(not comparable)

1. Through the night.