The compiled source code of any .Net application is called as an Assembly in .Net.
Assembly with as entry point, main method then they are called as Applications (.exe) in .Net
Assembly without as entry point is called as Class Library (.dll) in .Net
This four things packet is called as "PRE WRAPPER" (Portable Executable WRAPPER)
It maintains the info. about the header files that are used with in the application. We can identify where the header files are located.
Data about data is also called as MetaData.
The code present within the Assembly(Complied source code) will be in the format of MSIL instructions (byte Code).
Resource maintains the information about the external resources used within the application such as images, icons, cursors, audio-video clips etc.
It maintains the details about the attributes of an Assembly such as the product name, description, version etc.