Open-source software (OSS) is computer software that is available with source code: the source code and certain other rights normally reserved for copyright holders are provided under an open-source license that permits users to study, change, improve and at times also to distribute the software.
Open source software is very often developed in a public, collaborative manner. Open-source software is the most prominent example of open-source development and often compared to (technically defined) user-generated content or (legally defined) open content movements.
A report by the Standish Group states that adoption of open-source software models has resulted in savings of about $60 billion per year to consumers.
Read more about Open-source Software: History, The Open Source Definition, Proliferation of The Term, Non-software Use, Widely Used Open Source Products, Development Philosophy, Licensing, Funding, Comparison With Closed Source, Comparison With Free Software, Open Source Vs. Source-available, Pros and Cons For Software Producers, Development Tools, Projects and Organizations, Certification, Criticism