A particle system is a computer graphics technique used to simulate complex phenomena, such as fire, smoke, rain, or explosions. It consists of many small particles that represent individual elements of a larger effect. Each particle has properties like position, velocity, and color, which can change over time to create realistic animations. Particle systems are often used in video games and movies to enhance visual effects. They allow artists and developers to create dynamic and intricate scenes without needing to model every detail. By adjusting parameters, such as the number of particles or their behavior, creators can achieve a wide range of effects efficiently.