What is a free software?

Free software is usually available free or at cost distributionthrough other means, but it is not mandatory and therefore must not associate free software "free software" (usually referred to asfreeware) since, retaining its character of free, can be distributedcommercially ("commercial software"). Similarly, the "free software" or "free" sometimes includes the source code, however, this type of software is not free in the same sense asfree software unless ensure the rights of modification and redistribution of these modified versions of the program.