Processing is an open-source software and programming language that is mainly used for creating visual arts, animations, and interactive designs. It was created by Ben Fry and Casey Reas in 2001 and has been widely adopted in creative fields such as graphic design, architecture, and media arts.

Processing is built on top of the Java programming language and provides a simplified syntax that makes it easier to create complex graphical applications. Its library includes functions for drawing shapes, working with colors, manipulating images and sounds, and accessing input devices such as the mouse and keyboard.

The Processing environment provides an integrated development environment with a code editor, a library browser, and a visualization window where the sketches can be previewed and tested. Moreover, it also supports 3D graphics and can be used for creating games, simulations, and scientific visualizations.

Processing has an active community that develops and shares sketches, libraries, and tutorials online, making it easy to find resources to learn and create with Processing. It can also be integrated with other programming languages and tools, such as Python, Node.js, and Arduino, to expand its functionality and application areas.

Overall, Processing is a powerful tool for creative coding and digital arts, and it offers endless possibilities for exploring visuals and interactivity.