open-source

[oh-puh n-sawrs, -sohrs] /ˈoʊ pənˈsɔrs, -ˈsoʊrs/
adjective
1.
Computers. pertaining to or denoting software whose source code is available free of charge to the public to use, copy, modify, sublicense, or distribute.
2.
pertaining to or denoting a product or system whose origins, formula, design, etc., are freely accessible to the public.
open-source in Science
open-source  
Relating to source code that is available to the public without charge. Open-source code is often enhanced, improved, and adapted for specific purposes by interested programmers, with the revised versions of the code are made available to the public. For example, most of the code in the Linux operating system is open-source.