Source code is the code from which a software, application or website is created. It is a set of instructions written in a specific programming language to make the computer or other electronic device perform certain actions or achieve certain results.

The source code is the basic building block of any software or website and is written by developers to define the functionality and appearance of the software or website. The source code can be written in various programming languages, such as Java, Python, JavaScript, PHP, C++, C# and many others.

The source code is usually written by developers in a text editor or integrated development environment (IDE). Once the source code is written, it can be compiled or interpreted to run the application or website.

The source code can also be read, modified and improved by other developers. Many open source software and website projects allow the community to view and modify the source code in order to make improvements or extensions.

Overall, source code is a central component of software and web development and forms the basis for the creation of applications and websites. The ability to write and read source code is an essential skill for developers to create innovative and functional applications and websites.