Difference between VBA module name and Project Properties?

The project is the name of the entire VBA project for a macro-enabled file. The default project name is VBAProject. It can be renamed using component renaming rules (e.g., some characters not allowed, may not start with a digit).

A project can have many modules. Default module names are:

Sheet module: Sheetn
(Sheet modules are always created for all sheets; you cannot create or delete a sheet module)
UserForm module: UserFormn
Standard Module: Modulen
Class Module: Classn
Workbook Module: There is only one per file and it is named ThisWorkbook

When you try to rename the module the error message explicitly tells you:

Name conflicts with an existing module, project, or object library

A module and its project cannot have the same name.