Meaning of “light” - Learner’s Dictionary

light

noun us uk /laɪt/
The curtains shut out most of the light from the street.The moon cast a white light into the room.He could hardly see her in the dim light.The bomb exploded in a flash of yellow light.There's not much light in here.
BRIGHTNESS [ U ]

B1 the brightness that shines from the sun, from fire, or from electrical equipment, allowing you to see things:

bright/dim light
a beam / /ray of light
Light was streaming in through the open door.
DEVICE [ C ]

A2 a device that produces light:

car lights
to switch/turn the light on
They must be in bed - I can't see any lights on anywhere.
a light

a flame from a match, etc used to make a cigarette start burning:

Have you got a light, please?
set light to sth mainly UK

to make something start burning

in the light of sth also US in light of sth

If something is done or happens in the light of facts, it is done or happens because of those facts:

The drug has been withdrawn in the light of new research.

(Definition of “light noun” from the Cambridge Learner’s Dictionary © Cambridge University Press)