Limelight is a type of stage lighting once used in theatres and music halls. An intense illumination is created when an oxyhydrogen flame is directed at a cylinder of lime (calcium oxide), which can be raised to 2572°C before melting. The light is produced by a combination of incandescence and candoluminescence. Although it has long since been replaced by electric lighting, the term has nonetheless survived, as someone in the public eye is still said to be "in the limelight".
Limelight was first used in public in the Covent Garden Theatre in London in 1837 and enjoyed widespread use in theatres around the world in the 1860s and 1870s. Limelights were employed to highlight solo performers in the same manner as modern followspots. To this day, theatre followspots are often referred to as limes . Limelight was replaced by electric arc lighting in the late 19th century.