"Burning the Midnight Oil" is an idiom and like all idiomatic expressions has a hidden meaning. “Burning the Midnight Oil” means to work till late night. In olden times it meant working with the help of an oil lamp or candle light. In modern times people no longer use the oil lamp but the phrase continues to be used figuratively to mean working late into the night. Many professionals such as surgeons, attorneys, legislators burning the midnight oil are considered to be hard working and committed, sacrificing their personal time for their professional cause.
The origin of the idiom "Burning the Midnight Oil" goes back to the olden days, before the advent of electric lights when people used oil lamps to work or read in the darkness of the night. And those working hard through the night are burning the midnight oil. The expression is commonly used for students who study late through the night before an impending exam. The earliest use of the expression "Burning the Midnight Oil" can be found in the book Emblemes by the English author, Frances Quarles, written in 1635-
“Wee spend our mid-day sweat, or mid-night oyle;
Wee tyre the night in thought; the day in toyle.”
"Burning the Midnight Oil" means staying awake late and losing sleep as is generally done when people have to complete tasks in time. For example:
The idiomatic expression "Burning the Midnight Oil" may be seen in a positive light as it implies that a person is dedicated to meeting deadlines and is ready to work hard at the cost of his personal comforts. Sometimes "Burning the Midnight Oil" may have a negative connotation when students do not regularly work on their projects or studies throughout the term and end up working all through the night before an impending exam or submission.
In modern times "Burning the Midnight Oil" is largely used figuratively as people no longer use the light of a lamp to work. Professionals, who have to meet deadlines, stay late in the office after regular hours or work late into the night at home by burning the midnight oil. This way they can meet their deadlines and accomplish tasks without any disturbances. Its common for parents of newborn children to burn the midnight oil to look after their needs and more so when the child is suffering from an ailment and remains restless through the night.