Free Software
There are four fundamental freedoms associated with Free Software: 1. The freedom to run the program for any purpose (zeroth freedom).
2. The freedom to study how the program works and modify it as needed (first freedom). Access to the source code is a prerequisite for this freedom.
3. The freedom to redistribute copies and help others (second freedom).
4. The freedom to distribute modified versions (third freedom). This provides an opportunity for changes to benefit the entire community. Access to the source code is a prerequisite for this freedom.