壳 甲羅 殻 貝殻
A general term for the calcareous exoskeleton that protects the soft insides of many animals. Humans use them for a wide variety of purposes.
Most commonly seen as but not limited to seashell-dwelling mollusks on Danbooru. If you aren't tagging a mollusk, it's probably also turtle shell.
For the shells of eggs see eggshell. For spent ammunition, see shell casing.
The following tags implicate this tag:
holding_shell, mollusc_shell, seashell, shell_bikini, shell_earrings, and shell_necklace