Free and open-source software

"FLOSS", "FOSS", and "Free and Open-source" redirect here. For hardware, see Open-source hardware. For other uses of "Foss", see Foss (disambiguation). For other uses of "Floss", see Floss (disambiguation).
A screenshot of free and open-source software (FOSS): Fedora Linux 36 running the KDE Plasma 5 desktop environment, Firefox, Dolphin file manager, VLC media player, LibreOffice Writer, GIMP, and KCalc

Free and open-source software (FOSS) is software that is available under a license that grants the right to use, modify, and distribute the software, modified or not, to everyone free of charge. The public availability of the source code is, therefore, a necessary but not sufficient condition. FOSS is an inclusive umbrella term for free software and open-source software.[a] FOSS is in contrast to proprietary software, where the software is under restrictive copyright or licensing and the source code is hidden from the users.

FOSS maintains the software user's civil liberty rights via the "Four Essential Freedoms" of free software. Other benefits of using FOSS include decreased software costs, increased security against malware, stability, privacy, opportunities for educational usage, and giving users more control over their own hardware. Free and open-source operating systems such as Linux distributions and descendants of BSD are widely used today, powering millions of servers, desktops, smartphones, and other devices.[3][4] Free-software licenses and open-source licenses are used by many software packages today. The free software movement and the open-source software movement are online social movements behind widespread production, adoption and promotion of FOSS, with the former preferring to use the terms FLOSS, free or libre.

  1. ^ Feller 2005, pp. 89, 362.
  2. ^ Feller 2005, pp. 101–106, 110–111.
  3. ^ Hatlestad 2005.
  4. ^ Claburn 2007.


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