What is FOSS?
The term FOSS stands for Free and Open Source Software. Free Software is software that gives users the freedom to use on any number of computers, study the program and modify it, help others by giving them copies, and distribute modified versions of the program. In other words, the word 'Free' in Free Software refers to Freedom and not to zero cost. In order for a piece of software to satisfy the above conditions, its source code has to be available to the user. Open Source is another term used to denote more or less the same software. But the emphasis here is not on the freedom that Free Software gives but on the fact that the source code is available to everyone and, hence, the software is developed through a collaborative effort from several people. The term FOSS is used in order to give equal weightage to the two points of view.
To understand more about Free Software, please visit http://www.fsf.org/licensing/essays/free-sw.html.
A definition of what the term 'Open Source' means is available at http://www.opensource.org/docs/definition.php.
Please also visit the website of the Free Software Foundation of India at http://www.gnu.org.in to know about its activities and the issues that face the Free Software community in India.