What is application domain?

Answer 1

An application domain is a mechanism (similar to a process in an operating system) used within the Common Language Infrastructure (CLI) to isolate executed software applications from one another so that they do not affect each other.

Answer 2

An Application Domain is a logical container for a set of assemblies in which an executable is hosted.Application Domains, each of which is hosting a .NET executable. The first appdomain created when the CLR is initialized is called the default AppDomain and this default one is destroyed when the Windows process is terminated.

 An AppDomain can be independently secured.
 An AppDomain can be unloaded.
 Independently configured.
 No mutual intervention by multiple appdomains.
 Performance