Raspberry Pi is a small, affordable computer that can be used for various purposes. It was created to encourage the teaching of basic computer science and programming skills in schools. It has a credit-card-sized form factor and is built on a single circuit board. Raspberry Pi runs on Linux-based operating systems and has a wide range of applications, including as a desktop computer, media center, game console, and a tool for learning programming languages. It has gained popularity among hobbyists and professionals due to its versatility and low cost.