Nightlong

From Middle English *nihtlong, from Old English nihtlang ("lasting through the night, night-long, a night in length"), equivalent to night + long.

Full definition of nightlong

Adjective

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

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

Adverb

1. Through the night.