There isn't a specific scientific name for eggshell. However, it is considered to be part of the eggshell membrane, which is technically a calcareous shell.

Here's a breakdown:

* Eggshell: The hard, outer layer of an egg, primarily composed of calcium carbonate (CaCO₃).

* Eggshell membrane: The thin, flexible membrane that lines the inside of the eggshell. It is made of protein and is important for protecting the egg from bacteria and other contaminants.

* Calcareous shell: A general term for shells made of calcium carbonate, like the eggshell.

So, while "eggshell" is a common term, scientists might refer to it as part of the eggshell membrane or a calcareous shell for more precise descriptions.