Open source refers to the software that is released with source code under a license called GPL (General Public License) that ensures that derivative works will also be made available as source code and protects certain rights of the original authors, and prohibits restrictions on how the software can be used and  who can use it.

Open source is basically an approach to designing, development, and distribution offering practical accessibility to a product's source. It is one of the various possible designing approaches and strategic operation.

The open build model of operation and decision-making facilitates concurrent input of different plan, priorities and approaches, and differs from the more closed, centralized models of development. The objective and practices are generally applied to the peer production development of source code for software that is finally made available for public collaboration and is usually released as open-source software.

OSS (Open source software) is also defined as computer software for which the source code and certain other rights normally reserved for copyright holders are provided under a software license named GPL (General Public License. This lets users to use, change, and improve the software, and to redistribute it in modified or unmodified forms. It is very often developed in a public, collaborative manner. Open source software is the most prominent example of open source development and often compared to user-generated content. The term open source software originated as part of a marketing campaign for free software.