the atmosphere and outer space as viewed from the earth
"The pilot looked up at the vast sky, wondering if he could see the edge of the atmosphere or just more stars fading into darkness."
The atmosphere above a given point, especially as visible from the ground during the day.
"The sudden storm clouds darkened the sky just before the rain began to fall on our picnic."
In plain English: The sky is the blue area above us where we see clouds and the sun.
"The children pointed at the bright blue sky while playing in the park."
Usage: Use "sky" to refer specifically to the upper part of the atmosphere that is visible when looking upward, distinct from general weather conditions or clouds alone. It functions primarily as an uncountable noun in phrases like "the sky turned blue," though it can be pluralized ("skies") only when emphasizing different areas or atmospheric states across a wide region.
To toss upwards.
"The child threw the ball sky to see how high it would go."
In plain English: To sky means to move very quickly and easily through the air, usually by jumping or flying high above the ground.
"The plane began to sky dive straight toward the ground when its engines failed."
A surname.
"My neighbor, Sky, was so excited when she finally got her new house painted blue."
The word "sky" comes from the Old Norse word for "cloud," which entered Middle English with meanings ranging from mist to the sky itself. Its ultimate roots trace back to a Proto-Indo-European term meaning "to cover or conceal."