Defects in materials refer to any imperfections, flaws, or irregularities that may be found within the structure of a material. These defects can include missing atoms, dislocations, grain boundaries, cracks, impurities, and other types of structural irregularities. Understanding and characterizing defects in materials is crucial for predicting material properties, behavior, and performance in various applications. Researchers in this area study the formation, types, effects, and control of defects in materials to optimize material properties and prevent failure. Defects in materials are a broad and interdisciplinary research area that intersects with materials science, engineering, physics, chemistry, and other fields.