'Nightlong' definitions:

Definition of 'nightlong'

(from WordNet)
adjective
Lasting, open, or operating through the whole night; "a nightlong vigil"; "an all-night drugstore"; "an overnight trip" [syn: nightlong, all-night, overnight]

Definition of 'Nightlong'

From: GCIDE
  • Nightlong \Night"long`\ (?; 115), a. Lasting all night. [1913 Webster]