Define free software, open source software, and proprietary software (also called commercial software).?

A Free Software is an application/program which is free for the user to use,but the code i.e source code for the program is not released for public. eg:Skype.

An Open-Source s/w is one in which both source code and application is released for public,you can edit source code to make it better or simply use the application free of cost.These softwares are under GPL usually.eg:any linux application.

A propriety s/w is one for which user pays some money for using it.eg: Microsoft Office