The Chinese word for sky is
天空

tiānkōng

Translations for sky and their definitions

天空
1. n. sky; heavens; firmament
美好時光是那樣的短暫，宛若天空滑過的流星般轉瞬即逝。 - Happy times are so short; like a shooting star, they are gone in an instant.
2. adj. (literary, of the sky) open and vast

天
1. sky; heavens; heavenly; celestial
天空 - sky -
天黑了。 - It's getting dark. (lit. The sky is becoming black)
2. (mythology or religion) heaven as the abode of the gods or the blessed departed; heavenly
上天 - to go up to the sky; to go to heaven -
天意 - Heaven's will -
3. (mythology or religion) Heaven as an impersonal deity; (often translated as God)
天主 - God -
老天 - god -
我的天啊！ - Oh my God! -
天助自助者。 - God helps those who help themselves.
4. top; overhead
天橋 - footbridge -
天窗 - sunroof -
5. weather; climate
天很冷。 - It's very cold.
如果天晴，我們就去散步。 - If the weather clears, we'll go for a walk.
6. day (24 hours)
今天 - today -
明天 - tomorrow -
三天 - three days -
7. day (as opposed to night)
白天 - daytime -
三天兩夜 - three days and two nights -
8. period of time in a day
五更天 - just before dawn -
天不早了。 - It's getting late.
9. season
春天、夏天、秋天、冬天 - spring, summer, autumn, winter
黃梅天 - rainy season -
10. nature
天災 - natural disaster -
11. natural; innate
天生 - innate -
天性 - nature, personality -
天才 - genius -