Definition - What does Open Source mean?
Open source is a philosophy that promotes the free access and distribution of an end product, usually software or a program, although it may extend to the implementation and design of other objects. The term open source gained traction with the growth of the Internet because of the need to rework massive amounts of program source code. When source code is opened to the public it allows for the creation of different communication paths and interactive technical communities; it also leads to a diverse array of new models.
Techopedia explains Open Source
Open source revolves around the concept of freely sharing technological information so that it may be improved through multiple insights and viewpoints. Since the technology is open source, the amount of work that needs to be done is reduced because multiple contributions are added by many individuals. This concept existed way before the age of computers and even before the industrial age when people shared and improved recipes for food and medicine, for example.
In terms of open source software, the code is often freely downloadable and changeable as long as the user sticks to what is agreed upon in the software license agreement. Open-source software is usually under the General Public License (GNU), but there are other free licenses like the Intel Open Source License, FreeBSD License and the Mozilla Public License.