Assemblies are collections of compiled .Net types and resources grouped into a logical and physical unit (in the form of a .dll file or .exe file).
Assemblies are collections of compiled .Net types and resources grouped into a logical and physical unit (in the form of a .dll file or a .exe file - which has an entry point).
If a .exe is a .NET assembly then it also contains a CLR header as a data block inside the PE header.