I. ˈ ̷ ̷ˌ ̷ ̷ adjective
Etymology: night (I) + long
: lasting the whole night
a nightlong festivity
II. adverb
: through the whole night
working nightlong to save whom they could — Newsweek
I. ˈ ̷ ̷ˌ ̷ ̷ adjective
Etymology: night (I) + long
: lasting the whole night
a nightlong festivity
II. adverb
: through the whole night
working nightlong to save whom they could — Newsweek
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012