Burn the midnight oil


The phrase means to work late into the night. In 1635, this phrase was used by Francis Quarles in literary work which was a synonym to the word ‘lucubrate’. It literally meant to work by the side of a candle. To burn the mid night oil was the English way of saying that someone was working hard through the night because candles were used in the olden times to provide light at night. Recently, candles are no longer used as a source of light during the night but the phrase is still popular and is used figuratively, alluding back its use before electric lighting.