A shell or husk — a hard outer part that covers something (eggs, shells, pods, chaff).
ゆで卵の殻をむくのが苦手だ。
I'm not good at peeling boiled eggs' shells.
ガラスの破片が殻のように光って見えた。
The glass shards sparkled like a shell.
彼は殻に閉じこもっていたが、少しずつ変わってきた。
He was closed off in his shell, but has gradually been changing.