das Licht
light
The natural or artificial brightness that makes seeing possible.
Mach bitte das Licht an, es wird schon dunkel.
Please turn on the light; it's already getting dark.

light
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light
The natural or artificial brightness that makes seeing possible.
Mach bitte das Licht an, es wird schon dunkel.
Please turn on the light; it's already getting dark.

In everyday language, 'Licht' (light) is very often combined with the verbs 'anmachen' (to turn on) and 'ausmachen' (to turn off) when referring to artificial light sources. 'anschalten' (to switch on) and 'ausschalten' (to switch off) are also common.
Es ist zu dunkel zum Lesen, mach bitte das Licht an.
It's too dark to read; please turn on the light.
The plural 'die Lichter' (the lights) almost always refers to concrete light sources such as lamps or candles. Abstract brightness usually has no plural.
Die Lichter der Stadt leuchteten in der Nacht.
The lights of the city shone in the night.
The expression 'ans Licht kommen/bringen' (to come/bring to light) uses 'an das' (accusative) to express movement. If a secret becomes known by itself, 'kommt es ans Licht' (it comes to light). If someone uncovers it, 'bringt er es ans Licht' (he brings it to light).
Die Wahrheit über den Vorfall kam erst Jahre später ans Licht.
The truth about the incident only came to light years later.
In the idiom 'grünes Licht geben' (to give the green light), the person receiving permission is in the dative. What the permission applies to is often connected with 'für' + accusative.
Der Chef gab uns grünes Licht für das neue Projekt.
The boss gave us the green light for the new project.
The term 'ein großes Licht' (a great luminary) for a person is often used ironically today. It means that the person is actually not especially intelligent or capable.
Er hält sich für ein großes Licht, versteht aber die einfachsten Zusammenhänge nicht.
He thinks he's a great luminary, but he doesn't understand even the simplest connections.
sun
'das Licht' and 'die Sonne' are closely connected because the sun gives light. 'Licht' means brightness in general, whether it comes from the sun, a lamp, or a candle. 'Sonne' means the star in the sky, or the light and warmth that come from it. The words can be confused when talking about bright weather. If you mean the brightness, 'Licht' fits; if you mean the source in the sky or its warmth, 'Sonne' is more precise.

Am Morgen fällt weiches Licht durch das Fenster.
In the morning, soft light falls through the window.
Am Abend steht die Sonne tief über den Häusern.
In the evening, the sun is low above the houses.