Compressive strength is the strength a material has to support what is above it. Imagine that a material is needed to hold up a car. Would it be better to support it with a wood support or a steel one? While both might work the steel material has more compressive strength. If the material does not have as much tensile strength then more material is needed to support structures that are taller, such as the pyramids at Gizah or through the use of buttresses. This is also an important aspect of the post and lintel system, as well as the arch system.