Inside, Within
noun, の adjective
The kanji and the word are exactly the same. That means they share meanings as well. When this kanji is a word on its own, it's actually very often written in hiragana. Still, the kanji version of the word is worth knowing, too!
うち
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: There's something inside and you wanna get to what's within. Look inside. Ooh, cheese (うち)! Your favorite. Ooh cheese, how I love you.
このジャケット、内ポケットがいっぱいついてるよ。
This jacket has a lot of inside pockets.
このマスク、内がわはピンクなんです。
The inside of this mask is pink.
心の内をメッセージにしました。
I turned what was in my heart into a message.