“Burning the midnight oil” is an idiomatic expression that means to stay up late working or studying, often to meet a deadline or to accomplish a task. The phrase originates from the time when oil lamps were used for light, and staying up late would involve burning oil in a lamp to continue working after dark.
The expression conveys a sense of diligence, hard work, and sometimes sacrifice, as it often implies that the person is putting in extra hours, possibly at the expense of sleep or leisure. It can be used in both professional and academic contexts, suggesting that someone is dedicated to their responsibilities or goals. For example, a student preparing for exams might be said to be “burning the midnight oil” if they stay up late studying.