Open Source Software refers to software whose source code is made available to the public, allowing anyone to view, modify, and distribute it. This collaborative approach fosters innovation and community involvement, enabling developers to improve the software continuously. Popular examples include Linux and Apache. The open-source model promotes transparency and security, as users can inspect the code for vulnerabilities. Additionally, it often leads to cost savings for organizations, as they can utilize and adapt existing software without incurring licensing fees. This has led to a thriving ecosystem of projects and communities around open-source initiatives.