Sky
noun
The kanji and the word are exactly the same. That means they share meanings as well.
Since this word is made up of a single kanji, it should use the kun'yomi reading. When learning the kanji, you didn't learn that reading, so here's a mnemonic to help you with this word:
In the sky, you are the ruler. You are known as "The soarer!" (そら). Imagine your theme song and make sure it includes "soarer of the sky" or something awesome like that.
空は広い。
The sky is big.
夕べ、西の空はオレンジ色だった。
The western sky was orange yesterday evening.
雨のせいで、空には月が見えません。
You can't see the moon in the sky because of the rain.