Midair
Air, Space
noun
The kanji and the word are exactly the same. That means they share meanings as well.
This has the same reading as the kanji you learned, meaning you know the reading!
うちの猫はたまに口を開けて宙を見る時があります。
My cat occasionally opens her mouth and stares into space.
今は何もかもが宙ぶらりんで、やる気ゼロなんです。
Right now everything is in limbo and I have zero motivation.
ポケットから札束を取り出し、宙にバラまく時のコウイチの顔が好きだ。
I like the face Koichi makes when he takes bills out of his pockets and throws them into the air.