Definition: In physics, a billowier is a type of wave that occurs when an object or disturbance moves at a constant velocity relative to its surroundings. The motion of the object creates a disturbance in the surrounding medium, and as this disturbance propagates through the medium, it produces a wave with a wavelength that is shorter than the wavelength of the disturbance itself. Billowiers are important for understanding how waves propagate through media and can be used to simulate or analyze physical phenomena such as sound waves and light waves