A seashell; the shell of a mollusk often found on beaches, sometimes used as decoration or a keepsake.
子どもの頃、海岸で貝殻をたくさん拾った。
When I was a child, I picked up lots of seashells on the beach.
貝殻を使ってアクセサリーを作った。
I made accessories using shells.
波で打ち上げられた貝殻が砂浜に並んでいる。
Shells washed ashore by the waves are lined up on the sandy beach.