The term open-source refers to a decentralized model of production whose process and final result is freely available for the public to view, edit, and redistribute.
The open-source model is often presented in contrast with more centralized models of development such as those typically used in traditional industries and companies, where the creative process is usually confined to labs or R&D departments and the final product protected under copyright or any similar patent.
As recalled by Wikipedia, which constitute one of the best known examples of open source system, a main principle of open-source software development is peer production, with products such as source code, “blueprints”, and documentation available to the public at no cost. The open-source movement in software is arguably the most known, and began as a response to the limitations of proprietary code, and has since spread across different fields.
However, the same model is also used for the development of open-source appropriate technologies, and even open-source drug discovery.
Sources and references: