Particle Size Distribution (PSD) refers to the measurement and analysis of the sizes of particles within a given sample. It is often represented as a graph or chart, showing the proportion of different particle sizes present. Understanding PSD is crucial in various fields, including pharmaceuticals, materials science, and environmental studies, as it can influence the behavior and properties of materials. The distribution can be characterized using different statistical methods, such as mean, median, and standard deviation. PSD helps in determining how particles will interact, settle, or disperse in a medium, impacting processes like filtration, mixing, and reaction rates.