sky noun definition in Sky topic from the Oxford Advanced Learner's Dictionary

sky

 noun: Sky topic
[countable, uncountable] (pl. skies) the space above the earth that you can see when you look up, where clouds and the sun, moon and stars appear What's that in the sky? The sky suddenly went dark and it started to rain. the night sky a cloudless sky cloudless skies a land of blue skies and sunshine The skies above London were ablaze with a spectacular firework display.