Diffraction is a phenomenon that occurs when waves encounter an obstacle or a slit. The waves bend around the obstacle or slit, and the resulting pattern is called a diffraction pattern.
Diffraction is a common phenomenon that can be observed in many different types of waves, including light waves, sound waves, and water waves. It is a very important phenomenon in physics and engineering, and it has many applications in a variety of fields, such as optics, acoustics, and seismology.

The bending of waves when they move around obstructions or pass through narrow openings is called diffraction. So the answer is Diffraction.
Interference is the phenomenon that occurs when two or more waves interact with each other. The waves can either add together to create a new wave, or they can cancel each other out.
Reflection is the phenomenon that occurs when a wave bounces off a surface. The angle of reflection is equal to the angle of incidence.
Refraction is the phenomenon that occurs when a wave passes from one medium to another. The wave bends as it changes speed.