light1

noun

• 1the natural agent that stimulates sight and makes things visible:the light of the sun [in singular]:the street lamps shed a faint light into the room
• a source of illumination, especially an electric lamp:a light came on in his room
• (lights) decorative illuminations:Christmas lights
• a traffic light:turn right at the light
• [in singular] an expression in someone’s eyes indicating a particular emotion or mood:a shrewd light entered his eyes
• the amount or quality of light in a place:the plant requires good light in some lights she could look beautiful

Visible light is electromagnetic radiation whose wavelength falls within the range to which the human retina responds, i.e., between about 390 nm (violet light) and 740 nm (red). White light consists of a roughly equal mixture of all visible wavelengths, which can be separated to yield the colors of the spectrum, as was first demonstrated conclusively by Newton. In the 20th century it has become apparent that light consists of energy quanta called photons that behave partly like waves and partly like particles. The velocity of light in a vacuum is 299,792 km per second

• 2understanding of a problem or mystery; enlightenment:she saw light dawn on the woman’s face
• spiritual illumination by divine truth.
• (lights) a person’s opinions, standards, and abilities:leaving the police to do the job according to their lights

• 3an area of something that is brighter or paler than its surroundings:sunshine will brighten the natural lights in your hair

• 4a device that makes something start burning, as a match, lighter, or flame:he asked me for a light

• 5a window or opening in a wall to let light in.
• any of the perpendicular divisions of a mullioned window.
• any of the panes of glass forming the roof or side of a greenhouse or the top of a cold frame.

• 6a person notable or eminent in a particular sphere of activity or place:such lights of liberalism as the historian Goldwin Smith

verb (past lit /lit/; past participle lit or lighted)

• 1provide with light or lighting; illuminate:the room was lighted by a number of small lamps lightning suddenly lit up the house
• switch on (an electric light):only one of the table lamps was lit
• [no object] (light up) become illuminated:the sign to fasten seat belts lit up

• 2make (something) start burning; ignite:Allen gathered sticks and lit a fire (as adjective lighted or lit)a lighted cigarette
• [no object] begin to burn; be ignited:the gas wouldn’t light properly
• (light something up) ignite a cigarette, cigar, or pipe and begin to smoke it:she lit up a cigarette and puffed on it serenely [no object]:workers who light up in prohibited areas face dismissal

adjective

• 1having a considerable or sufficient amount of natural light; not dark:the bedrooms are light and airy it was almost light outside

• 2(of a color) pale:her eyes were light blue