You can find RMS' full definition of ''freedom'' at http://www.gnu.org/philosophy/free-sw.html

To sum it up:

'''{{{Free software}}} is a matter of liberty, not price. To understand the concept, you should think of free as in {{{free speech}}}, not as in {{{free beer}}}.'''

Free software is a matter of the users' freedom to run, copy, distribute, study, change and improve the software. More precisely, it refers to four kinds of freedom, for the users of the software:

 * The freedom to run the program, for any purpose ('''freedom 0''').
 * The freedom to study how the program works, and adapt it to your needs ('''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 improve the program, and release your improvements to the public, so that the whole community benefits ('''freedom 3'''). Access to the source code is a precondition for this.