A kind of theatrical lantern invented in the mid 19th Century. A blowtorch fed with a mixture of oxygen and hydrogen (producing a very hot flame) was focused on a block of lime causing it to incandesce with a brilliant white light which could be focused through a lens to create a spotlight. The term is now applied to anyone/thing which has become a major focus of attention, ie. to be 'in the limelight'.

An obsolete source of intensely bright light, most recently used in followspots. See limes. Derived from a burning jet of oxygen and hydrogen impinging on a rotatable cylinder of lime.

a focus of public attention; "he enjoyed being in the limelight"; "when Congress investigates it brings the full glare of publicity to the agency"

a lamp consisting of a flame directed at a cylinder of lime with a lens to concentrate the light; formerly used for stage lighting

in the limelight: the primary focus of lighting on stage. Originates from when followspot s used a block of lime, heated until it incandesced, as their light source.

Limelight is a type of stage lighting once used in theatres and music halls. Although it has long since been replaced by electric lighting, the term has nonetheless survived, as someone in the public eye is still said to be "in the limelight". An intense illumination is created when an oxyhydrogen flame is directed at a cylinder of lime (i.e. calcium oxide), which can be raised to white heat without melting.