Idiom
day and night and night and day
Theme: TIME
all the time; around the clock. (Reversible.)The nurse was with her day and night.The house is guarded night and day.
day and night
noun
1
a light ale. Rhyming slang, first recorded in 1960, and still fairly current UK, 1960.
2
light (illumination). Rhyming slang UK, 1992