A "brake" is a mechanical device used to slow down or stop the motion of a vehicle. It works by creating friction against the wheels, which reduces their speed. Common types of brakes include disc brakes and drum brakes, each with its own design and function. Brakes are essential for safety in vehicles like cars, bicycles, and trains. When a driver presses the brake pedal, it activates the braking system, allowing the vehicle to decelerate or come to a complete stop. Regular maintenance of brakes is important to ensure they function effectively and safely.