Open Source, Free Software, Free Open Software (FOSS) or Free Libre Open Source Software (FLOSS) are all alternative names for software that is created by open collaborative communities. The Free Libre indicating free as in freedom or "free speech" rather than free as in gratis or "free beer"'; that is FLOSS may have a purchase price but you are guaranteed several freedoms.

• Freedom to run the program, for any purpose (freedom 0).
• 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.
• Freedom to redistribute copies so you can help your neighbour (freedom 2).
• 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.

These freedoms are enforced by using copyright and licensing laws to guarantee that the software will be kept available for community use and not made proprietary property. There are many, many licenses with different levels of enforcement with "Free" licenses being strongest; for example the GPL. There are also parallel schemes for documentation and creative media such as pictures; for example the Free Document Licence as used by wikipedia and the Creative Commons licenses. In comparison proprietary software protects ownership and exploitation of the program by hiding the source code. Other types of software licence known as Freeware or Shareware is also low cost but you do not have the same freedoms. You can find out more about the legal aspects in Understanding Open Source Software and Open Source Licensing: Software Freedom and Intellectual Property Law.

FLOSS projects operate as on-line collaborative communities (see below) which provide rapid development and easy access to support. Having a large number of contributors ensures high levels of usability and quality by peer-review. Contributions from people at all levels of skill and experience are actively encouraged with many being involved as volunteers. This means that users can have a direct say in what features are included. A crucial idea is that software can rapidly improve if the program source code is freely available to everyone.

Cost of ownership of FLOSS is low with the developers generating revenue by means other than charging for the program and support often free available. To the user FLOSS can mean high quality software at a good price and with excellent support and quick fixes. To the developer FLOSS can mean having mature initial code to work with and a large pool of contributors.

The main FLOSS organisations are:

• Open Source Initiative (OSI) for Open Source Software [DEFINITION]
• Free Software Foundation (FSF) for Free Software [DEFINITION]

Definition

• The Wikipedia definition of FLOSS.