Shell
Husk
noun
The kanji and the word are exactly the same. That means they share meanings as well. This word isn't limited to animal shells though! It covers seed shells, or husks, too.
Since this word is made up of a single kanji, it probably uses the kun'yomi reading. You did not learn this reading, so here's a mnemonic to help you:
Shells are a good defense against からて chops. You can't get hurt if you have a nice strong shell to protect you from that からて-chopping weirdo who just showed up out of nowhere.
蟹の殻はこの皿に入れてください。
Please put crab shells on this plate.
麦の殻を取ったら、その次はどうするの？
What do we do after removing the husks from wheat?
種の殻を突き破って、芽が出てくる瞬間を捉えたビデオを見ました。
I watched a video that captured the moment when a seed breaks through its shell and sprouts.