When a software program is open source, it means the program's source code is freely available to the public. Unlike commercial software, open source programs can be modified and distributed by anyone and are often developed as a community rather than by a single organization.
Christensson, Per. "Open Source Definition." TechTerms. Sharpened Productions, 30 October 2008. Web. 07 November 2016. <http://techterms.com/definition/opensource>.