The absorption coefficient is a measure of how much light or other electromagnetic radiation is absorbed by a material as it passes through. It quantifies the fraction of energy lost due to absorption per unit distance traveled in the material. Higher values indicate that the material absorbs more energy, while lower values suggest that more energy passes through. This coefficient is important in various fields, including optics, acoustics, and material science. It helps in understanding how materials interact with different wavelengths of light or sound, which is crucial for applications like designing optical devices or assessing soundproofing materials.