“Burn the midnight oil” means to work late into the night, especially when putting in extra effort to finish a task or study. It describes staying awake beyond normal hours to continue working. The focus is on dedication or necessity, not just being awake at night. The idiom often implies commitment to completing something important.

Word/Phrase	Definition
Burn the midnight oil	To work late into the night to finish a task or study
Stay up late	To remain awake until a late hour
Pull an all-nighter	To stay awake all night to work or study

The idiom comes from a time when people used oil lamps or candles to provide light at night. Working late meant literally burning oil to keep the light on while continuing to work. The phrase became common in English to describe late-night effort. The imagery connects hard work with the practical need for light after dark.

People use this idiom most often about studying for exams, finishing work deadlines, or preparing important projects. It is common in academic and professional settings where extra hours are needed. The tone is usually neutral or slightly admiring of the effort involved. It does not describe leisure activities or simply staying up late without a purpose.

Rule
Use this idiom when someone is working or studying late to complete a specific task
Do not use this idiom for staying up late for entertainment or socializing
The idiom fits best in situations of deadline pressure or urgent preparation

“Burn the midnight oil” is standard and understandable in both spoken and written English. It is slightly formal or literary compared to very casual expressions. In modern speech, people might also say “pull an all-nighter” for staying up the entire night. Both expressions can appear in workplaces, schools, and media, but the tone shifts with the choice of phrase.

Word/Phrase	Definition
Burn the midnight oil	To work late into the night, often with a sense of diligence
Pull an all-nighter	To stay awake all night to finish work or study, usually with urgency
Work late	To continue working beyond normal hours, without implying the whole night

“Burn the midnight oil” means working late into the night to complete something important, with origins in oil lamps used for nighttime work. It is best used for describing diligent effort on tasks or studies, not for casual late nights. The idiom remains common in English for situations of extra work or urgent deadlines.