Free software is software that is made available under a licence that grants the user specific rights that are not typically granted for proprietary software. The Free Software Foundation lists four freedoms needed to meet its definition of free software:
- The freedom to run the program for any purpose
- The freedom to study how the software works and modify it to meet your needs
- The freedom to distribute copies of the software
- The freedom to publish modifications to the software
In order to fulfil these requirements access to the source code is essential, so free software is a type of open source software. The right to distribute the software may be subject to a clause that ensures that future recipients of the software have the same freedoms.
Free Software is not the same as freeware. Free software may be sold for a fee, and freeware may not grant the user the freedoms necessary to qualify as free software. In order to avoid confusion between the two meanings of free some people describe free software as "free (libre) software".