Shell-like is often used to describe anything that looks or feels similar to a shell, whether it is a natural object or a man-made product. Some synonyms for shell-like include conchoidal, carapace-like, crustaceous, and testaceous. Conchoidal is used to describe a surface or an edge that looks like it has been chipped away from a glassy material. Carapace-like is used to describe something that resembles a crab or a turtle shell. Crustaceous is used to describe something that is hard, brittle, and crusty. Testaceous is used to describe something that looks like a test or a shell of a mollusk or snail. All of these synonyms can be used interchangeably with shell-like, depending on the context in which it is used.