Compressive strength is the measure of a material's ability to withstand loads that tend to reduce its size. It indicates how much pressure a material or structure can resist before it is crushed or deformed. This property is crucial in construction and engineering, as it helps determine whether a material is suitable for supporting weight and withstanding various forces. Materials like concrete, stone, and metals are often tested for compressive strength to ensure safety and durability in buildings, bridges, and other structures.