{n. phr.} The work period lasting from sundown to sunup, when one has to work in the dark or by artificial light. * /"Why are you always so sleepy in class?" Professor Brown asked Sam. "Because I have to work the graveyard shift beside going to school," Sam answered./
GRAVEYARD SHIFT
Meaning of GRAVEYARD SHIFT in English
Dictionary of English idioms . Словарь английских идиом. 2012