What FOSS Really Mean?

Posted by Shaifali's Blog on December 26, 2014

FOSS consist two terms Free and Open Source. But are these both terms different? An open source software is always free software. Isn’t it. This question always blow my mind, why we use both the terms if they mean same. So finally decided to search and get answer. Here putting that only.

Let us understand about each of the two terms individually.

Free Software

Free Software does not mean  the software is free in context of Money/Price. Here Free represents the freedom users have, the liberty users have to read, use, copy, modify and share the code and software(both changed and real one). So it is about rights, privileges and not cost. Users are free to control the program the way they want.

Four degrees of freedom that a free software provide can be read from The Free Software Definition.

Open Source

The origin of this term is to avoid the confusion of the term free software but later on it become something with different perspective. Open Source software means the code of software is public and users are free to modify and enhance and distribute it.

But this is the same as Free Software. So what’s the difference? We are again at same place.


Though both the term refer to all most same thing but there is some small difference. Free Software are more powerful while Open Source license are a bit more supportive to commercial areas. Any program made using free software will also be always published under free software license, but this is not the case with open source software. Any open source software which is not free software if modified can be published without open source license. That is why most of the license that are Free Software are also OSI(Open Source Initiative) approved, that is they are also open source license.

We should not use both terms interchangeably, there are examples of licenses which are only any one type approved and not other. CECILL License v2 is FSF approved while not open source and NASA Open Source Agreement is open source while not Free.

But the real difference between both the term is still a mystery! I will add more stuff with proves if I will find.

Few more resources to read about same: