sky
n. countable A2 Elementary Oxford US //ˈskaɪ// UK //skˈaɪ// sky
n. the space above the earth where you see the sun, moon, stars, and clouds.
n. the region of the atmosphere and outer space seen from the earth. Often used with the definite article 'the'.
The sky is very blue today.
As the sun began to set, the sky turned a beautiful shade of pink and orange.
Astronomers spent the entire night scanning the clear desert sky for any sign of the passing comet, hoping to capture high-resolution images before dawn.
Usage
Usually used in the singular with 'the'; the plural 'skies' is common in literary contexts or when describing weather conditions.