Se f.ex:
http://www.google.com/search?hl=en&lr=&ie=UTF-8&q=define%3A+open+source&btnG=SearchHvor der f.ex. står:
– A somewhat ambiguous term that refers to software that is released with its source code. The fact that the source code is provided does not necessarily mean that users can modify and redistribute the source code. The term is sometimes used interchangeably with “free software,” although they are not always the same. (Also, see Public Domain and Shareware.)