Difference between ASP.NET Web Application and ASP.NET Web Site

Web Site 

Just a bunch of files and folders. There’s no project file. Code-generation and compilation of web pages (such as .aspx, .ascx, .master) is done dynamically at runtime, and changes to these files are detected by the framework and automatically re-compiled. You can put code that you want to share between pages in the special App_Code folder, or you can pre-compile it and put the assembly in the Bin folder.

Web Application  

 Because Web Applications contains files that are not meant to be deployed, such as project and code files, there’s a Publish command in Visual Studio to output a Web Site to a specified location.

Difference between ASP.NET Web Application and ASP.NET Web Siteaption