Diffraction is a phenomenon that occurs when waves, such as light or sound, encounter an obstacle or aperture and bend around it, instead of traveling in a straight line. This bending causes the waves to spread out and interfere with each other, creating a pattern of alternating light and dark areas called diffraction pattern. Diffraction is commonly studied in various fields such as physics, chemistry, and engineering to understand the behavior of waves and how they interact with objects in their path. Applications of diffraction include the design of optical lenses, analysis of crystal structures, and measurement of particle sizes.