'day-and-night' definitions:

Definition of 'day-and-night'

(from WordNet)
adjective
At all times; "around-the-clock nursing care" [syn: around-the-clock, day-and-night, nonstop, round- the-clock]

Definition of 'day-and-night'

From: GCIDE
  • day-and-night \day-and-night\ adj. same as around-the-clock.
  • Syn: around-the-clock, nonstop, round-the-clock. [WordNet 1.5]