burning the midnight oil

working very long hours, often into the night What doctors do know is that burning the midnight oil is bad for your health.

Etymology: from the use of oil to provide light before the invention of electricity

Name	Pronounced	Usage
Veselko	-	Croatian, Serbian
Lysimachus	-	Ancient Greek (Latinized)
Krystal	KRIS-təl	English
Ilsa	IL-sah	German
SemİH	-	Turkish
Arcangelo	-	Italian