There are four types of assemblies in .NET:

Static assemblies
These are the .NET PE files that you create at compile time.

Dynamic assemblies
These are PE-formatted, in-memory assemblies that you dynamically create at runtime using the classes in the System.Reflection.Emit namespace.

Private assemblies
These are static assemblies used by a specific application.

Public or shared assemblies
These are static assemblies that must have a unique shared name and can be used by any application.

An application uses a private assembly by referring to the assembly using a static path or through an XML-based application configuration file. While the CLR doesn't enforce versioning policies-checking whether the correct version is used-for private assemblies, it ensures that an
application uses the correct shared assemblies with which the application was built. Thus, an application uses a specific shared assembly by referring to the specific shared assembly, and the CLR ensures that the correct version is loaded at runtime.

In .NET, an assembly is the smallest unit to which you can associate a version number;