sky

American  

[skahy] / skaɪ /

noun

plural

skies

1. the region of the clouds or the upper air; the upper atmosphere of the earth.

   airplanes in the sky; cloudy skies.

2. the heavens or firmament, appearing as a great arch or vault.

3. the supernal or celestial heaven.

   They looked to the sky for help.

4. the climate.

   the sunny skies of Italy.

5. Obsolete. a cloud.

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verb (used with object)

skied, skyed, skying

1. Informal. to raise, throw, or hit aloft or into the air.

2. Informal. to hang (a painting) high on a wall, above the line of vision.

verb phrase

1. sky up (of prey, when flushed) to fly straight upward.

idioms

1. to the skies, with lavishness or enthusiasm; extravagantly: Also to the sky

   to praise someone to the skies.

2. out of a / the clear sky, without advance notice or warning; abruptly: Also out of athe clear blue sky

   An old beau phoned her out of a clear sky.

sky British  

/ skaɪ /

noun

1. (sometimes plural) the apparently dome-shaped expanse extending upwards from the horizon that is characteristically blue or grey during the day, red in the evening, and black at night

2. outer space, as seen from the earth

3. (often plural) weather, as described by the appearance of the upper air

   sunny skies

4. the source of divine power; heaven

5. informal the highest level of attainment

   the sky's the limit

6. highly; extravagantly

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verb

1. rowing to lift (the blade of an oar) too high before a stroke

2. informal (tr) to hit (a ball) high in the air

sky Scientific  

/ skī /

1. The atmosphere, as seen from a given point on the Earth's surface. The sky appears to be blue because the wavelengths associated with blue light are scattered more easily than those that are associated with the other colors.

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sky More Idioms  

More idioms and phrases containing sky

• blow sky-high
• out of a clear blue sky
• pie in the sky
• reach for the sky

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Other Word Forms

• skyless adjective
• skylike adjective

Etymology

Origin of sky

First recorded in 1175–1225; Middle English, from Old Norse skȳ “cloud,” cognate with Old English scēo “cloud”

Explanation

Want to see the sky? Go outside and look up! That’s assuming you’re not on Mars, of course. Everything you see above the surface of the Earth is the sky. Astronomers use the term "celestial sphere" for the sky. It's the space that includes everything we can see from our earthbound perspective, including clouds, stars, the sun, and the moon. If your uncle takes you out for ice cream and says, "The sky's the limit!" he means that there is no limit at all—you can order anything, even an enormous banana split.

Example Sentences

SpaceX’s regular Falcon 9 launches have helped the company blanket the sky with roughly 10,000 Starlink satellites, enabling broadband connections even in remote and war-torn regions.

From The Wall Street Journal • Apr. 15, 2026

DaVinci, Bopbop, Barrington, Damien, Janine, Margaret, Susan and Rosie stand 22 feet tall, kissing the sky.

From Los Angeles Times • Apr. 14, 2026

An American flag, bald eagles and jet fighters are in the sky behind him.

From The Wall Street Journal • Apr. 13, 2026

A resident has told of the "bizarre" moment he watched a suspected meteorite fly through the night sky.

From BBC • Apr. 13, 2026

The birds are drowned out by the thrum of tires, but they flit from branch to forest floor to sky, and you know they like to sing while they move.

From "Legendary Frybread Drive-In" by Cynthia Leitich Smith