Bullet is an open-source physics simulation library primarily used for robotics, gaming, and visual effects. It provides a robust framework for simulating rigid body dynamics, soft body dynamics, and collision detection. The library is designed for real-time performance and is compatible with various programming languages, including C++, Python, and Java. Bullet is widely utilized in both academic research and commercial applications, making it a versatile tool for developers seeking to integrate physics simulations into their projects.