1. n. [Geology, Geophysics, Formation Evaluation]

A measure of a material’s strength. The uniaxial compressive strength (UCS) is the maximum axial compressive stress that a right-cylindrical sample of material can withstand before failing. It is also known as the unconfined compressive strength of a material because confining stress is set to zero.

Alternate Form: unconfined compressive strength,  unconfined compressive strength