Free and open-source software (FOSS) is computer software that can be classified as both free software and open source software. That is, anyone is freely licensed to use, copy, study, and change the software in any way, and the source code is openly shared so that people are encouraged to voluntarily improve the design of the software.
(http://en.wikipedia.org/wiki/Free_and_open-source_software)
Explore other prominent free and open source software projects.