What does "shear strength" measure in materials?

Shear strength is a critical property of materials that indicates their ability to withstand shear forces without failing. Shear forces occur when two opposing forces are applied parallel to a surface, which can cause deformation or failure in materials. The correct choice highlights that shear strength is fundamentally about measuring how well a material can resist these types of forces.

Understanding shear strength is essential in applications such as structural engineering, metalworking, and materials design, where the ability to endure sliding or shearing stresses is paramount for ensuring structural integrity and durability. In contrast, the other options focus on different material properties: compressive resistance deals with forces pushing inward, thermal conductivity relates to heat transfer capabilities, and elasticity pertains to a material's ability to deform under stress and return to its original shape. Each of these properties serves a different purpose and is important in its own context, but they do not define shear strength.