Day turns night.

Meaning: This means that the daytime changes into nighttime as the sun sets. It's like saying, The period of light changes to darkness as the sun goes down.

Choice of Words: Day is the period of time between sunrise and sunset. Turns is a verb that means to change or become something else. Night is the period of time between sunset and sunrise. When you put them together, "Day turns night" is a sentence that describes the natural transition from day to night.

Alternative Expressions

The sun goes down.

Meaning: This sentence means that the sun is setting, which is when it moves below the horizon and it gets dark outside.

Choice of Words: The sun is the star at the center of our solar system. Goes down means to move below the horizon, which is the imaginary line that divides the sky and the land or sea.

It gets dark outside.

Meaning: This sentence means that the sky or the environment outside is becoming darker, which is what happens when the sun goes down.

Choice of Words: It refers to the sky or the environment outside. Gets dark means to become darker or less bright.

Related Expressions