free & proprietary software

The four software freedoms as defined by the Free Software Foundation

– The freedom to run the program as you wish, for any purpose (freedom 0).
– The freedom to study how the program works, and change it so it does your computing as you wish (freedom 1). Access to the source code is a precondition for this.
– The freedom to redistribute copies so you can help your neighbor (freedom 2).
– The freedom to distribute copies of your modified versions to others (freedom 3). By doing this you can give the whole community a chance to benefit from your changes. Access to the source code is a precondition for this.

Also see:

https://en.wikipedia.org/wiki/The_Free_Software_Definition
https://en.wikipedia.org/wiki/Free_software_license
https://en.wikipedia.org/wiki/Free_software
https://en.wikipedia.org/wiki/Proprietary_software
https://www.gnu.org/philosophy/free-sw.html
https://www.gnu.org/philosophy/proprietary.html